Zoë goes digging for answers as Sarah starts to spiral. Hamza is under pressure to keep a lid on the crisis.

Sarah winds up on an unexpected road trip. Zoë begins pulling threads left behind by Joe and suspects something bigger is at play.

While hiding out, Sarahs learns more about Downey. Zoë ruffles feathers as she seeks new collaborators for her investigation.

Zoë makes a startling discovery that expands the scale of the conspiracy. Sarah and Downey trek north, revealing their pasts along the way.

A dangerous game of cat and mouse begins on the train to Scotland. Sarah and Zoë try piecing together Dinah's exact location.

Downey and Amos converge as the race to find Dinah reaches a breaking point. Sarah must take a leap of faith.

Everything Sarah has fought for hangs in the balance.