Welcome to The Trigger, the fifth add-on content pack for Alien: Isolation. Can you make Sevastopol safe? You’ve been given a box of explosives and the locations to set them. All you need to do now is pull the trigger… and stay alive. - Features three all-new Survivor Mode maps. Can you survive and get the highest score? - Play as Ricardo and learn the truth behind the explosives on board Sevastopol. - Avoid security alarms, take on Working Joes and above all, survive the Alien.

During the Xenomorph outbreak on Sevastopol, marshal Waits contacts deputy Ricardo who was located in Prisoner Processing and announced that he had supposedly located the Drone in an unspecified area on the station. He instructs the deputy to meet up with him as fast as he can and also suggested locking down the area as well. However, Waits' lead was proven to be false as the Drone was in fact revealed to be in Prisoner Processing with Ricardo still in it. Ricardo before reaching an elevator, managed to collect numerous prisoner tags from deceased inmates on the way, collect the visitor registry data and lockdown the area's armory. Waits informs Ricardo about Gardiner, a fellow marshal who was supposed to have delivered a package, was not checking in. The elevator stops at Seegson Synthetics with Ricardo exploring the area. The area is filled with corpses, with the one closest to the package presumably being Gardiner. The "package" is revealed to be explosives, with Waits intending to use them against the Alien. Ricardo takes them from a table and leaves for the elevator, but not before finding a private message sent from Nina Taylor to Waits regarding the flight recorder. The elevator is revealed to be dysfunctional, with Ricardo being forced to turn the power back on for it to work. Ricardo revamps power to the area whilst also unintentionally activating numerous Working Joe androids in the process that began to prowl the perimeter. Ricardo also activates an alarm, attempting to lure the Alien to him so that it can follow him to the area where he will set the explosives. He later calls for the elevator and escapes. Ricardo reaches the area, the Alien having followed him. Under the duress of the Drone, Ricardo manages to send a conformation message to Waits to update the marshal on his progress and activate an evac alarm, encouraging all remaining survivors within the quarters to flee the area. Ricardo eventually plants the explosives and takes leave in an elevator. As the screen cuts to black and displays the score menu, a muffled explosion can be heard, shortly followed by the beginning of Diane Verlaine's distraught message sent to Sevastopol, (audio log 32). This reveals that the explosion that severed the EVA line and separated Amanda from Taylor and Samuels, thus kick-starting Ripley's journey throughout Sevastopol, was in-fact the result of Ricardo's set explosives.