Season 3 Episode 8: Ghosts

"In an alternate future, Amy Stoker was a member of the London Field Team. However, after a botched operation in Athens failed to prevent her abduction, the future changed. Only now, she is back – and more than that, other children who had been abducted from time are also returning. While the team attempt to decipher this puzzle and its implications, the fallout from the operation with the Russians and the Americans sends ripples throughout the QIA. Meanwhile, Sarah is being plagued by ghosts from her past, and after everything she has been through, she finds herself being pushed closer and closer to the edge of sanity…"