Secrets:Chronology

Chronology of events
Note that the days are given as a rough indication. Feel free the actual date. Try to preserver order, though, if possible. Of course, actions of the PCs may change the events yet to come.

Before the game starts

 * Day 0: End of the Battle for Earth. Victory in Space. Reapers retreat. Earth, Palaven, Thessia are still occupied and Processing Camps are still processing at full capacity, converting civilians into Reaper Troops. The Citadel is still occupied by Reaper Troop.
 * Day 1: The Salarian STG starts a campaign of manipulation to keep the Joint Fleet unified against a new enemy: the Krogan.
 * Day 1-30: Quresh Reconciliation crews rig together hundreds of disabled and damaged spaceships orbiting around Earth into a network of galactic communication stations designed as a temporary replacement for the Citadel's communications nexus. This network reenables many of the subnetworks of the Extranet, which had been disabled when the Reapers took control of the Citadel.
 * Day 5: Cerberus propaganda across the galaxy starts to claim that Victory in Space was the act of Cerberus, and leaks some details of the Crucible to the public. The Joint Fleet is quick to deny.
 * Day 5+: Cerberus remnants starts attempting to make contact with the Illusive Man, the Reapers themselves and the Collectors.
 * Day 15-70: Third Battle of London. The Alliance Navy controls the city for a while but eventually needs to retreat before the relentless pressure of Reaper Troops. Similar attempts on Palaven and Thessia end with the same result. The Joint Fleet must admit that grounded Reaper Troops are still extremely efficient and that taking back their capital planets without nuking them in the process may take years and mobilize most of the available resources of the Joint Fleet. Space domination, however, makes evacuation of civilians possible. A new doctrine is adopted on highly-populated worlds: organize coordinated lightning strikes on Processing Camps to free and evacuate as many civilians as possible, then relocate them to colonies.
 * Day 20: Several cases of a new virus are reported. The virus is clearly artificial, probably of Reaper origin, and seems infect any species. So far, its only reported symptom is an increased appetite.
 * Day 25: Cerberus launches a covert operation on Reaper-controlled Illos to try and send a few unit to the Citadel, in the hope of locating the Illusive Man.
 * Day 25: A force of Awakened Collectors, supported by a Collector Cruiser, briefly takes control of the Martian Archive. They stay only a few hours and leave before the Joint Fleet has time to send enough firepower to threaten a fully manned Collector Cruiser.
 * Day 30-100: Negotiations between civilian authorities of major species, regarding the reformation of the Council. Dozens of factions from the most influential species all pretend to represent their species – including some who claim to speak for Cerberus, and a delegation of Awakened Collectors claiming to speak for the Protheans. Calls are made by several factions to exclude the Salarian Union from the Council, due to their lukewarm support of the war effort. Negotiations lead nowhere.
 * Day 40: The Salarian Union launches a second network of galactic communication stations around Sur'Kesh, complementing the rigged stations orbiting around Earth.
 * Day 45: First attempt to retake the Citadel ends in slaughter.
 * Day 50: The Joint Fleet launches Task Force Herakles, whose single objective is to hunt down Cerberus traitors. Former Cerberus scientists are offered amnesty if they surrender and join the effort to cleanse the galaxy of Reaper activity. Joint Fleet intelligence believes that the largest remaining Cerberus base is beyond the Omega-4 relay and installs a permanent blockade.
 * Day 50: Researchers of the Galactic Health Organization concludes that the virus infects anyone who travels through a Mass Effect Relay, and that all the persons present in the fleets around Earth during the Battle for Earth have already been infected. Virus is dubbed the Relay Virus. Still no meaningful symptoms.
 * Day 60+: The Joint Fleet adopts a "domination from space" doctrine for less-populated worlds: evacuate civilians into safe zones if possible, then concentrate firepower against Reaper bases. This strategy proves mostly effective, but Reaper troops are quick to entrench themselves deep underground, which makes it impossible to entirely guarantee entire elimination.
 * Day 60+: Awakened Collector ships are witnessed performing lightning strikes all over the galaxy, taking control of specific points for a few hours, before retreating immediately. Joint Fleet intelligence speculates that they are attempting to extract Prothean artifacts and/or DNA.
 * Day 75: Researchers of the Galactic Health Organization determine that the virus is slowly converting both organic beings and Geth into bio-synthetic constructs. The information is immediately classified.
 * Day 80: Husks are found hiding in a ship of civilians being evacuated from Earth. New protocols are put in place to try and avoid such cases.
 * Day 80: A landing spaceship collides with an orbital factory around Sur'Kesh. While the incident is initially believed to be an accident, responsibility is claimed by a group that makes itself known as the Vengeful Ghosts, as reprisals for apparent absence of the Salarian Union since the beginning of the Reaper War.
 * Day 90: Examination of an Asari embryo suggests that the virus may be transmitted from mother to child.
 * Day 90+: Second terrorist attack by the Vengeful Ghosts against Salarian assets. Further attempts are made to destroy factories or civilian and military infrastructures. Most, but not all, attempts are foiled.

After game start

 * Day 100: The Joint Fleet performs a bloodless military coup against civilian authorities of Human and Asari civilizations. The new governing body, named Joint Watch, is effectively a militarized version of the Council. The Quresh Reconciliation (the uneasy alliance of Geth and Quarian) is invited to join the Human, the Asari, the Turian and the Salarian. The Krogans are not.
 * Day 100+: War Engineers around the galaxy and other people with tech-extended OmniTools and a hacking background start to realize that the Relay Virus offers an OmniTool interface. The Joint Fleet tries to suppress the information but eventually fails as the infection progresses and more and more hackers make the discovery independently.
 * Day 105: After Krogans vow to cease fighting on Palaven if they do not get a seat in the Joint Watch, they are accepted with a probationary status.
 * Day 106: The Salarian Dalatrass is arrested for treason, along with key members of her staff. Logs found incriminate them as Indoctrinated Reaper agents. Her replacement vows that the new Dalatrass will offer full support in the fight against Reaper Troops, Cerberus and the Relay Virus. The STG promises to expose numerous high-ranking Indoctrinates in the Joint Fleet and its allies.
 * Day 110: A Specter investigating disappearances in the Turian colony of Talos finds out what can best be described as an undercover unit of Marauders harvesting citizens and converting them one by one into more of their kind. While most members of the unit are killed, along with their conversion apparatus, some of the Marauders manage to escape in a civilian ship, to a destination unknown. The investigation will determine that the source of this infection was indoctrinated Turian civilians evacuated from Palaven. The Joint Watch revises its evacuation protocols to attempt to prevent further contagions. It quickly becomes clear that tracking all the escapees from Reaper-controlled planets is impossible. Experts attempt to devise new techniques to detect the Indoctrinated.
 * Day 110: Salarians expand their "buy now, pay later" military exports to offer Weapon Locker-type minifactories and warships to partner Krogan Clans. Construction of Carrier-sized Precision Orbital Bombardment Platforms begins. Response from Krogans and civil opinion across the galaxy is unconvinced.
 * Day 115+: The Joint Watch officially declares the Batarian Hegemony extinguished, making its former territories a new frontier, ripe for conquest, for anyone strong and crazy enough to challenge the omnipresent Reaper outposts. Adventurers of all species – including Batarians – start forming raiding parties to plunder or conquer whatever they can. Krogan Clans start talking of expansion.
 * Day 120: The Joint Watch starts the campaign to take back Illos, currently controlled by Reaper troops, hoping to retake the Citadel through the Illos Conduit.
 * Day 125: Creation of Quick-Response Force Fire Within to respond to the threat of Indoctrinated attempting to propagate Reaper contagion.
 * Day 125+: An Awakened Collector Cruiser enters the orbit of Illos. After short negotiations, they join the fight to retake that world. This is the first concerted Collector/galactic battle since the arrival of the Reapers. Their hive mind makes them invaluable for coordinated ground/air/space strikes. The strategy of embedding Collectors in Joint Fleet units and embedding Joint Fleet strategists aboard Collector ships becomes known as the Illos Pairing.
 * Day 130: Researchers of the Galactic Health Organization manage to trigger self-destruction of the Relay Virus in an organism. Unfortunately, this self-destruction causes immediate liquefaction of the carrier organism. Cerberus agents within the GHO immediately leak samples to Cerberus labs. Comparison is positive: the liquid is the Reaper blood obtained from the Collector Base on the Tartarus Sea.
 * Day 130: Desperate for information on the Reaper and their agenda, Cerberus attempts to reactivate the Reaper Larva from the Collector Base, and use it to communicate with the Illusive Man, or whoever ended up controlling the Crucible.
 * Day 130: For the first time since the departure of the Reapers, Reaper troops offer to parlay. A Banshee calling herself The Queen of the Dark Lands claims to speak for all Reaper troops in Europe.
 * Day 140: The sole survivor of the Alliance Cruiser Victory and Beyond, disabled during the Battle for Earth, is recovered, after 6 months on a derelict ship. He suffers from hallucinations, multiple personality disorder, dehydration, lack of vitamins, but also yellow skin and all the symptoms of cannibalism. More worrying is the fact that he is nearly 3 meters tall, inhumanly strong, displays an advanced level of biotics despite the fact that he been classified biotics-negative, and that his organism shows advanced progress of conversion to bio-synthetics. Examination suggests that he somehow absorbed mass, knowledge and biotics from other crew members through the Relay Virus. Again, the Alliance attempts to suppress this information, but too late. Within a few days, most factions have deduced that the Relay Virus is actually the Reaper Endgame. For the moment, civilian populations are unaware of that fact.
 * Day 145: The Joint Watch fleet on Illos, with Awakened Collector support, has taken full control of the subcontinent holding the Conduit. Preparations start to stage an assault on the Citadel through the Conduit. Awakened Collectors do not join this effort, but maintain a ground presence. They are shortly joined by a large force of Batarian mercenaries, who apparently worship them as saviors.
 * Day 150: For the first time, a Quarian + Geth team manages to hack the body of an infected Human by interfacing with the Relay Virus. He will not be the last one.
 * Day 150: The STG takes down the Space Train smuggling network. This network had been taken over by Marauders and was used to covertly smuggle Reaper troops and Indoctrinates across the galaxy. All bases of operation of the Space Train are destroyed by the STG and the Joint Watch.
 * Day 160: The Joint Watch starts implementing strong discrimination in its population, between infected and non-infected, suspected of Indoctrination and non-suspected. This is complicated by the fact that most of the Navy of the Joint Watch species is infected. Several species and private companies start working on FTL Arks without Mass Effect capability, containing only non-infected, non-Indoctrinated citizens or embryos.
 * Day 170: The Omega-4 Blockade Fleet, with the help of Awakened Collectors and Batarian mercenaries, crosses the Relay and takes the Cerberus Station and the Collector Base after just a few hours of fight against strong automated defenses. The Joint Watch navy finds a large but unmanned Fleet of Cerberus warships and infiltration ships, an empty station and an empty base. Intelligence speculates that Cerberus has found another unmapped Relay somewhere on the Tartarus Sea. The Joint Fleet is ordered to stand down and let Awakened Collectors take possession of the Collector Base.
 * Day 180: Survivors of a pirate attack in Terminus Space tell the tale of a group of Asari commandos devouring their victims. The attributions of Task Force The Fire Within are extended to hunt down and terminate all Relay Virus cannibals.
 * Day 190: The United Outer Colonies become the first movement to take arms against the Joint Watch.