Mass Effect 2 often feels like a race against the clock. With the Collectors abducting human colonists, both Commander Shepard and the Illusive Man know they need to act fast to find out what the Collectors are up to and how to stop them before it's too late. When a unique opportunity to inspect a derelict Collector ship floating adrift after encountering a Turian patrol presents itself, Shepard has no choice but to investigate the ship.
This mission is triggered after completing a certain number of required quests, like recruiting eight squadmates (Zaeed and Kasumi count toward this). Once the requirements have been met, the mission must be dealt with right away, as Shepard won't be able to do anything else after being prompted to speak with the Illusive Man, who instructs Joker to take the Normandy to the ghost ship.
Mission: Explore the Cruiser
Upon entering the ship, walk forward. EDI will be in constant contact with Shepard, and early on, she informs them that the ship's signature matches the one they encountered on Horizon. After rounding the bend, Shepard encounters the first evidence of the colonists' brutal fate: stasis pods. Advancing forward, they happen upon piles of dead bodies, and Shepard can earn morality points: +2 Paragon for saying they might be better off, or +2 Renegade for noting they can't be helped now.
Move down the tunnel and salvage the Collector Tech (worth 7500 credits) on the right, then grab the med-kit. Up ahead is a control terminal, which will trigger a cutscene when approached. Shepard contacts EDI, who runs an analysis on the experiments the Collectors were running and determines they were comparing their own genetics to human genetics. On the Normandy, EDI discovers something even more shocking and unexpected: Collector DNA matches Prothean DNA, confirming that the Protheans aren't actually extinct, but were genetically modified to become Reaper slaves. Shepard can earn +2 Paragon for saying, "They were Protheans," and either another +2 Paragon for commenting on the horror of their fate, or +2 Renegade for saying they'd be better off dead.
When the cutscene ends, Shepard can access a pile of weapons on the ground that will prompt a menu screen displaying one of three weapon options. Choosing from a weapon Shepard does not already have access to will grant them opportunity to train in a new weapon type. They may also choose a weapon they are already proficient in to gain the most powerful weapon in-game for that category. For example, an Infiltrator Shepard proficient in sniper rifles already could pick up the Widow Anti-Material Rifle here instead of gaining access to training in assault rifles or shotguns. Before moving on, pick up the element zero cache nearby.
As Shepard and crew advance through the ship, they come upon a vast open room containing numerous pods. EDI will note that, despite some of the pods containing bodies, she detects no life signs. Head upward and on the right there will be more Collector Tech to salvage (15,000 credits) before reaching another control terminal that gives a Damage Protection research upgrade.
While moving up a long ramp, Joker informs Shepard over the comm that he and EDI discovered this ship is the one that destroyed the Normandy two years earlier. At the top of the incline, they enter a vast open area with more than enough pods to abduct everyone in the Terminus Systems. At this, Shepard concludes the Collectors must be planning on going after Earth. Upon reaching what appears to be a dead end, there is another console to access. It is wise to save the game here before accessing the terminal.
Mission: Fight Harbinger and the Collectors
When Shepard accesses the terminal, EDI can directly link with the ship and begin collecting and analyzing its data. Things start to get strange aboard the Normandy, with Joker seeing the Collector General on his screens while the area Shepard and their squad are in begins to tremble. Joker informs Shepard that there was a power surge, but EDI took care of it. EDI then tells Shepard it was not a malfunction, but a trap, and she's struggling to maintain contact because there's someone else in the system.
The platform Shepard is on surges upward with the squad. As they recover their balance, EDI says she will maintain contact. In the distance, the first Collectors seen aboard the ship begin spiraling on similar platforms toward Shepard. Take cover and begin taking out the enemies, which will occasionally embody Harbinger like they did on Horizon. If Shepard can shoot and kill them during transformation, Harbinger is temporarily stopped from overpowering them, but will quickly move on to another Collector to ensure Shepard gets his message.
There are three waves of platform-carrying enemies in this fight, and depending on the difficulty level, it can quickly escalate into one of the hardest battles in the game. On higher difficulty, use biotic powers like Stasis to hold the Scions in place long enough to take them out, and use the heavy weapon in Shepard's arsenal to destroy masses of enemies efficiently. Pay attention to Harbinger and prevent him from coming into point-blank range, which he will always be attempting to do.
Once the battle ends, EDI informs Shepard she can regain control if they access the controls again. Doing so moves the platform back to where it came from, and while sailing through the sky, EDI announces that the distress signal that drew them in was not Turian. It was a trap all along, and it's clear that the Illusive Man set Shepard and their squad up for this encounter.
Mission: Escape the Collector Ship
The Collector ship powers up and prepares to take off with Shepard and their squad inside, so race back to the entry point. The Collectors will not make it easy to escape, as they will shut down doorways and force EDI to reroute the path. After jumping off the platform, EDI opens the first door. Grab the med-kit nearby. Keep moving forward, salvaging another piece of Collector Tech along the way, before entering battle on the lower level. Take cover as Collector drones fly in and Harbinger begins taking them over. Battle through and move down the ramp into the next fight.
Take cover and keep an eye on the left walkway, which the Collectors may use to try and flank Shepard and their squad. As before, Harbinger overtakes the drones and taunts Shepard. Take him out and stay in cover through four to five waves of husks and Collectors. Once they've been dispatched, drop down into the next area and prepare for another fight.
This time, there's a Praetorian with its beam focused on Shepard. From cover, take out the other enemies as quickly as possible, then shift focus to the Praetorian. Chip away at it, always moving in circles and staying out of its reach. Once it's been dealt with, head through the pathway EDI opens up and salvage more Collector Tech. Grab the Tech Damage Research Upgrade from the console nearby and keep moving.
The next battle requires slow strategy, as advancing too quickly means becoming flanked. Take out the waves of Collectors and husks, moving forward and into position to take out the final Scion blocking the next doorway. Head through that doorway and prepare for an overwhelming number of husks standing between Shepard and the exit. It isn't easy, but Shepard can bypass this fight entirely by running through the husks and triggering the escape cutscene. Otherwise, keep shooting them and avoid getting cornered because they will swarm in and overwhelm Shepard, making it impossible to get away.
Once back aboard the Normandy, confront the Illusive Man about setting Shepard and their team up. There are multiple opportunities to earn morality points in this conversation, with Shepard gaining +5 Paragon or Renegade for simply completing the mission and additional chances to get +2 on either side depending on what they say to the Illusive Man. Once the debrief is complete, meet with the squad. Shepard will get +2 Paragon for agreeing or +2 Renegade for saying they still don't like it. Still more points can be earned by talking to Kelly Chambers after, with +2 Paragon for telling her to thank the crew or +2 Renegade for saying Shepard didn't need EDI's help.