The Indus Valley

Julian thought he was Indiana Jones and instead of listening to the person who was with him, he opened a box and set free...Savitar. It's too bad I never watched Harry Potter, because dude has been playing with the Philosopher's Stone all this time.

HR has decorated STAR Labs.

Cisco keeps seeing Dante around STAR labs.

Julian lies to Barry about finding the stone.

Barry heads over to Earth 3 to chat with Jay Garrick, who is having a battle with the Trickster, who is just like the Joker. Now we know why he wears the helmet. Savitar is the first man granted speed and when he comes to earth he's getting ready to challenge the man who he feels is about to usurp him.

Wally is training with HR and his only concern is whether he's faster than Barry.

Cisco tells Caitlin what he's been seeing and shares with her his favorite Christmas memory, and she shares a memory of her and her father watching snow fall.

Iris has news for Barry about the excavation in India four years ago. Barry and Jay go after Savitar and Alchemy and Barry pulls off Alchemy's hood.

Julian thinks The Flash is full of it. He acts as if he has no recollection of events at all.

Joe and Wally have a fight. Joe says something key. It's like Wally's asleep at the wheel and someone else is at the controls. Barry goes back to Julian. Has he been been blacking out? 

When his sister died, he saw her. She told him if he found the stone, it would bring her back to him. He would have done anything to find it. Now Cisco is with the box and he's going to be possessed by the stone, too.

Caitlin appeals to Cisco to close the box while Barry and Wally fight Savitar. 

Barry puts Julian into a goofy cap and Savitar talks. One shall betray you. One shall fall. One shall suffer fate far worse than death. Future Barry trapped this dude in eternity, and he wants Barry to feel his wrath.

Barry and Jay come up with a relay race to throw the box into the speedforce. When they do it, Barry gets pulled into the future, five months from now. Savitar kills Iris.

Jay tells Barry to live his life. The future is mutable.

They all have Christmas together. Iris gets Barry a wallet and he signs a lease on a wonderful new apartment for them both.