Barry feels guilty for what happened to Caitlin and Mark comes up with a plan which makes everyone skeptical. Meanwhile, Red Death looms in Central City and commands that failure is not an option. Joe asks Cecile to make a choice which leads Cecile to think about the greater good. Allegra and Chester take a step in a new direction. Lastly, old friends pay an unexpected visit to S.T.A.R. Labs.
Elenco: Grant Gustin , Candice Patton , Danielle Panabaker , Jesse L. Martin , Carlos Valdes , Tom Cavanagh , Danielle Nicolet , Kayla Compton , Brandon McKnight , Hartley Sawyer , Rick Cosnett , Tom Felton , Keiynan Lonsdale , Jessica Parker Kennedy , Jon Cor .