Rook was a Communications Officer aboard the fuel depot Sphacteria orbiting the gas giant Pylos. He was one of the crew members to suddenly experience a Xenomorph infestation after encountering a mysterious vessel.
As Captain Hassan was complaining about being unable to contact an unknown vessel approaching their perimeter, he asked Engineering Officer Wascylewski if anything on their ship stayed fixed. Wassy shifted the blame to Rook, much to his annoyance. Park pointed out that the ship contained Hypersleep chambers and that the crew may still have been asleep. Rook was less than sure, speculating that they may have been "raiders" like the ones they had had to deal with last year. He suggested to "let them float".
Hassan told the others that they would take their shuttle to investigate whilst Rook stayed aboard the Sphacteria in the flight deck.
The crew later returned with three passengers, all horribly burnt after Wascylewski and the others attempted to open the chambers. As they regrouped at the flight deck, Wassy deduced that if the crew initiated emergency procedures aboard the ship, then the vessel would autopilot them to the nearest corporate location, in this case, the Sphacteria. Rook suggests that perhaps "they were in one hell of a hurry to hit the cryotubes". Hassan was later interrupted by medic Harrow who called him down to the medbay.
Rook followed Hassan and the others to the medbay where they looked on in shock as Harrow and Park attempted to hold down a seizing passenger. Though Rook questioned why Harrow could not give them more sedatives, he retorted that he gave them as much as he could give. Suddenly, two Chestbursters erupted from two of the passengers' chests, with the crew looking on in horror as the creatures escaped into the depths of the ship.
Rook was the first of the crew of the Sphacteria to perish, being taken and presumably killed by the now adult Xenomorphs.
Rook was one of the more fractious and immature members of the Sphacteria who didn't try hiding his bad mood. He seemed to specifically dislike Wascylewski, who was constantly annoying and teasing him.