Abra Kadabra was the latest villain to grace The Flash. It couldn't have come at a worse time as Barry and the team were busy trying to come up with a way to to save Iris from being killed by Savitar.
Abra Kadabra came to Earth-1 to steal components to build a time machine return to the 64th century, when he is originally from. But after being captured he revealed that he knows how to stop Savitar and he said he'd spill his guts if Barry let him go.
Barry didn't let him go, instead he made a plan to travel to the future so he could devise a plan to stop Savitar. Obviously Barry has forgotten that every time he time travels he changes not only history but causes fluxes in the speed force and draws the ire of speed wraiths. Oh well.
To make matters worse, Caitlin technically died on the episode after having a run-in with one of Abra Kadabra's grenades. Julian made a last ditch effort to resuscitate her but only ended up unleashing her inner Killer Frost.