Is amnesia contagious? People are left with holes in their memory. Others disappear but no seems to notice, or care. One college boy and his friends are dragged into a mystery when someone they know goes missing. Clara tries to find the Doctor when everything she knows is gone. A strange girl may hold the key to the mystery plaguing Roswell, if only she could remember.

The future has recreated the past, but along with it came Jack the Ripper, one even deadlier than the original. When the Doctor, Clara, and company are stranded in this unforgiving future, they must work together with one Sherlock Holmes to uncover the Ripper's deadly secrets before they become the next victims.