Archer, Trip, and Reed return from an alien barter town with Rajiin, an alluring woman seeking to escape her life as a sex slave. But once on board, her beguiling sensuality proves irresistible to the Enterprise crew. She uses her alien mental powers on them to steal biometric data about humans so her Xindi overlords can make a bio-weapon. Two Xindi ships attack the NX-01 to retrieve Rajiin. Meanwhile, Trip and T'Pol attempt to synthesize trellium-D to insulate Enterprise from further destruction by the spatial anomalies of the Delphic Expanse. 

A powerful and lonely telepath named Tarquin begs Hoshi to visit his faraway planet. Smitten with her, he offers to part with crucial intelligence on the Xindi only after she visits. But when Enterprise returns to pick up Hoshi, Tarquin refuses to let her go. He wants her to be his new Companion.