Following its accidental launch the Astraeus returns to Eureka and the crew discovers four years have elapsed in an instant. The crew quickly learns leadership has changed, procedures have changed and relationships have changed while they were gone and none of it for the good.
Warren Hughes makes one of unexpected visits to evaluate the Astraeus crew. Unfortunately his evaluations coincide with crew members' tendencies to swap minds with Jack. And some of the swaps happen during amorous activities that further stress the relationships of the crew's lovers.
Allison's also brilliant brother visits the newlyweds to give Jack a hard time but Jack's intellect rises to the occasion. Henry and Zane work on freeing Holly from her virtual reality cage while struggling just to keep her alive.