Rook was a Communications Officer aboard the fuel depot Sphacteria orbiting the gas giant Pylos. He was one of the crewmembers to suddenly experience a Xenomorph infestation after encountering a mysterious vessel.
As Captain Hassan is complaining about being unable to contact an unknown vessel approaching their perimeter, he asks Engineering Officer Wascylewski if anything on their ship stays fixed. Wassy shifts the blame to Rook, much to his annoyance. Park points out that the ship contains Hypersleep chambers and that the crew may still be asleep. Rook is less than sure, speculating that they may be "raiders" like the ones they had to deal with last year. He suggests to "let them float".
Hassan tells the others that they'll take their shuttle to investigate whilst Rook stays aboard the Sphacteria in the flight deck.
The crew later returns with three passengers, all horribly burnt after Wascylewski and the others attempt to open the chambers. As they regroup at the flight deck, Wassy deduces 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 is later interrupted by medic Harrow who calls him down to the medbay.
Rook follows Hassan and the others to the medbay where they look on in shock as Harrow and Park attempt to hold down a seizing passengers. Though Rook questions why Harrow can't give them more sedatives, he retorts that he gave them as much as he could give. Suddenly, two Chestbursters erupt from two of the passengers' chests, with the crew looking on in horror as the creatures escape into the depths of the ship.
Rook is the first of the crew of the Sphacteria to perish. And is taken and presumably killed by the now adult Xenomorphs.
Rook is one of the more fractious and immature members of the Sphacteria who doesn't try hiding his bad mood. He seems to specifically dislike Wascylewski, whom is constantly annoying and teasing him.