Enterprise visits an ancient Vulcan spiritual sanctuary, despite T'Pol's concerns that her human colleagues will be an awkward and disruptive presence there. Upon landing, they discover that the monastery has been forcibly taken over by the Andorians, a paranoid and highly excitable race of aliens with a long history of conflict with the Vulcans.

The Enterprise crew alters course to investigate the mystery of Terra Nova, a legendary Earth colony whose inhabitants mysteriously disappeared decades ago. But when they arrive, they confront descendents of the colonists who have become more alien than Archer could ever have imagined.

When Trip is dispatched to assist a Xyrillian ship with its power source problems, he is delighted to have a friendly encounter with one of the ship's female engineers. However, shortly after returning to Enterprise, he discovers that their seemingly innocuous interaction has led to a surprising result.

Archer sends an away team to a habitable, luscious planet for observation. But when a storm occurs, the team begins to experience paranoid delusions.