Jo displays atypical behavior after a DNA scan malfunctions, unfortunately it's while she's interim sheriff because Carter is undergoing a 48-hour DOD recertification test.

It's space week in Eureka, and everyone is gearing up for the rocket race - except for Carter. General Mansfield is in town for the big Race to the Moon, and is debriefed on a new oxygen-generating fluid designed, called TAP, for colonizing Mars. When the question about someone using TAP to fuel their rocket, the whole town of Eureka is in danger and it is up to Kevin to save the day this time. Will he do it, or will Jack come back to see charred remains of his friends?

Carter's romantic surprise for Allison turns deadly when they're trapped in a sinking marine lab with time and oxygen quickly running out.