In 2599, the crew of the BUGS 2 mission lands on Mars to clear the planet of the evolved cockroaches an earlier terraforming effort left behind, Shokichi Komachi and Ichirou Hiruma among them. The genetically modified soldiers find Terraformars whose strength, armor, and intelligence have grown well past anything the expedition prepared for, and the landing turns into a massacre. This OVA adapts the manga's Bugs 2 arc, part of the main Terra Formars story rather than a side tale.