After hearing of a supposedly haunted alien ship on a desolate planet, Archer decides to cannibalize the wreck to replenish Enterprise's supplies and discovers the vessel is inhabited after all. While exploring the ship, the Enterprise crew encounters some ghostly apparitions and an alien race surviving despite insurmountable odds. Trip helps repair their derelict vessel and is befriended by Liana, an attractive humanoid alien who develops feelings for him.

Hoshi thinks she is to blame for a series of misunderstandings that sent a group of visiting aliens off the Enterprise in a huff. As the Kreetassans depart, a strange, symbiotic alien creature boards Enterprise capturing a few crew members, including Archer and Trip. This unidentifiable parasite cocoons them in its web, feeding off their bodies to survive. With the captured crewmembers' lives in jeopardy, an insecure Hoshi, under T'Pol's command, faces her biggest challenge by finding a way to communicate with the lifeform and persuade it to return to its home planet.