The feline Space Marines chapter is involved in purging a ship from extra-terrestrial monsters.
A mob of the Kung-Fu creatures takes over a spaceship heading to the Planet Dorkon with important supplies. A distress signal from the ship reaches the Terra and a Space Marine detachment is sent to cleanse the space ship from the invaders.
The boarding party commanded by Captain Pussycat reaches the destination point and the feline Space Marines find themselves inside a Kung-Fu Creature colony. The Assault Terminators led by Commander Zaleski rush at the Xenos, pounding them with thunder hammers and lightning claws, while their female companions backup them from firearms.
When the space ship's corridor splits into two smaller ones, the Assault Terminators move past the left corridor and their firearms-armed companions take the right one. The melee weapon squad reaches the engine department, which has been turned by the aliens into their breeding area. The infestation seems too huge for clearing with melee weapons, thus Stan contacts Penelope to provide flamethrowers.
Meanwhile, the female part of the company is repelling the Kung-Fu Monsters attacking in waves. The Xenos gang up on Arlene and she falls, being unable to repel the monsters. The rest of the team manages to help Arlene, despite she needs medical help after the combat.
The two squads reunite in the ship's control room, which turns out to have been taken over by a huge Kung Fu Creature, differing from those the Space Marines encountered so far. Despite its odd appearance, the monster falls quicky under firearm barrage and melee weapons' blows. The only survivor from the ship's original crew turns out to be a medical officer, who administers help to wounded Arlene.
The Saint Marcus Lions ("Space Mousers") 1st Company
- Penelope Pussycat as the company Captain
- Mona Pussycat as the Company Commander
- Stanisław Zaleski as the Company Commander
- Delilah Pussycat as the Company 1st Lieutenant
- Kitty diVono as the Company's Lt. Commander
- Ian Zaleski as the Company's 2nd Lieutenant
- The Bennett Triplets as Company's Ensigns
- Arlene as a Space Marine
- The Kung-Fu Creatures as the Xenos
- This episode is a parody of Games Workshop's games Warhammer 40.000 and Space Hulk.
- The Space Mouser chapter is based on the Ultramarines from Warhammer 40.000 canon.