 Enterprise encounters an unusually large comet and captain Archer orders the crew to follow the phenomenon for a couple of days. T Pol finds out the comet s surface contains eisilium, a very rare element that even Vulcan scientists haven t yet closely examined. Just when Reed and Mayweather are sent to drill to retrieve some of it, the Ti Mur, a Vulcan ship arrives. Vanik, its captain, tells they re interested in human s curiosity about the comet, but captain Archer doesn t trust it. Especially not after Tucker discovers a coded message has been sent to T Pol from the Ti Mur.