Four teenagers hit Sebastian shortly after he becomes a zombie, and he kills one of them. When the body turns up, Liv eats the brain and tries to find out…

When DeVoe assaults an A.R.G.U.S. facility to complete his Enlightenment Machine, Barry realizes the only way he can stop him is if he allows Cisco and Caitlin to accompany him…

When Barry needs help transporting a dangerous meta, he calls on a new friend for help – Leo Snart AKA Citizen Cold. Meanwhile, Cisco becomes suspicious of Harry.

As Barry’s trial for the murder of Clifford DeVoe begins, Iris and Joe must decide how far they are willing to go to keep Barry out of prison.

Crowley turns to Dean for help to locate the First Blade, the only weapon that can kill Abaddon. However, they soon discover that the trail leads to Cain… the Father…