Holden and Fred deal with infiltrators on Tycho. Drummer’s past comes back to haunt her. Amos returns to Baltimore. Alex and Bobbie’s investigation on Mars leads to rogue soldiers.

Wendy takes a career risk to relocate and join the team full time. Holden and Bill find it harder to keep the emotional intensity of work at bay.

Wendy considers an offer. Holden and Bill struggle to communicate the meaning of their findings to the judicial system in the baffling Altoona case.

Bill and Holden consult with Dr. Wendy Carr to begin classifying their subjects. They receive surprising news.