Higgins is on guard duty at a camp on Klendathu. Whilst in front of the gates he sees a trooper staggering along. As he talks to the trooper a new type of Bug, hence known as an Impostor Bug, bursts out of the suit. The Impostor is a Bug that approximates the size and shape of a human and is able to fit inside stolen power suits. As such they present a major threat to the security of S.I.C.O.N. forces. The troopers manage to kill the bug but not before it manages to drop Lt Razak and knock his helmet off. After the attack, the Roughnecks are ordered to rescue the crew of a downed transport ship. When they get to the crashed ships location they discover that the crew have been captured by Bugs. As the squad track them Bugs back to their nest Lt Razak collapses - it seems he has been infected by spores carried by the Impostor Bug. Doc and Flores go to find the fungus responsible so Doc can synthesise an antidote whilst the rest of the squad keep tracking the Bugs.