Widespread panic is caused in a small community after numerous deaths are linked to killer cockroaches, and a government agricultural agency is discovered to have set up a secret experiment involving insects.

Mulder and Scully investigate a series of disappearances and attacks around a lake where Mulder believes that the local legend about a lake monster may be all too real. Frustrated Scully insightfully confronts Mulder about the futility of their work on the X-Files.