The Flash Season 1 Episode 13 The Nuclear Man

After the mysterious death of Dr. Martin Stein, a suspicious fire erupts at S.T.A.R. Labs, and Barry races to save Caitlin when she becomes trapped inside. Upon his arrival, Barry discovers that the fire occurred as a result of the F.I.R.E.S.T.O.R.M. formula, which Stein and his former partner Ronnie Raymond were working on. Intending to investigate the situation, Barry enlists the help of Dr. Stein's wife, but soon realizes that the pair is not who they seem and may have a connection to the explosion at S.T.A.R. Labs that gave Barry his powers. As Barry tries to uncover the truth behind their connection to the nuclear man, he must also deal with a new threat from Captain Cold and Heat Wave, who are wreaking havoc on the city. With his abilities and the help of his friends, Barry must stop the villains and uncover the truth about F.I.R.E.S.T.O.R.M. before it's too late.