In the late 21st century, an army of insect-like aliens has invaded the Earth. Relying on collective group mind and telepathic messages, these creatures have overthrown the dominant race on their home planet, Siria, assimilating their technology. As the planet became uninhabitable, the new Sirians have ventured into deep space, hoping to find a new home. Their goal was to find vertebrate creatures, in which they could lay their eggs; they have chosen the Earth for that reason. To avert this terrible threat, the Fist of Earth organization sends a fighter pilot named Viper to protect the planet, navigating their strongest weapon - the starfighter XF5700 Mantis.
XF5700 Mantis Experimental Fighter is a mission-based space combat simulation, and a sequel to Warhead. The game utilizes real space (Newtonian) physics for ship navigation. Mission objectives usually involve eliminating alien ships while protecting Viper's wingmen. The game continues the plot of Warhead in its 90 missions.
The original box had a sticker blurbing, "If you liked that "other" space flight sim, you'll love Mantis!" The other sim was, of course, Wing Commander. And anyone familiar with marketing knows a statement like that almost assuredly means the product in question is bad.