It is 1952, and Captain Maxwell Carter, USMC, is having a bad day. After waking up naked in the middle of the freezing desert with an alien device around his neck, he is picked up by a mysterious Air Force officer who offers him a ride to a nondescript military test facility, but no clarity as to the situation. Once there, Captain Carter learns that he is part of a nightmarish experiment - he is pregnant with an alien baby. S4 follows the gestation of the Trugollion/Human hybrid infant and its effect on Carter (his sudden ability to read minds at random, his desire to consume live birds, his emotional break downs), and the struggle of Captain Jake Mason, charged with the care and nurturing of Captain Carter. Faced not only with an emotionally unstable, mind reading pregnant Marine, Mason must also cope with the manipulative Colonel Thadeus Drake, a career hungry Air Force doctor/mad scientist/evil administrator who seeks to entangle Mason in his twisted plans, and “Angie”. Angie, the liaison for the Trugollion Empire, has been stuck on Earth awaiting her replacement since 1947. Sent to Earth in a pleasing human female form, Angie struggles with her desire to return to her home world and her lust for Captain Mason.