The Flash season 1 returns with an all new episodes tonight, Tuesday, 17 February at 8pm on The CW.

Episode 14 is titled Fallout, which will introduce viewers to a time travel plot.

Click here to watch the episode online.

The official synopsis reads as follows:

After the nuclear explosion separates Ronnie (guest star Robbie Amell) and Dr. Stein (guest star Victor Garber), Barry (Grant Gustin) and the team believe both men are safe. Caitlin (Danielle Panabaker) is thrilled to have her fiancé back and prepares to resume their life together while Dr. Stein returns to his wife. However, when General Eiling (guest star Clancy Brown) targets Firestorm, Ronnie and Dr. Stein must decide if they are safer together or apart. Meanwhile, Mason Bridge (guest star Roger Hayworth) tells Iris (Candice Patton) that there is something secretive going on at S.T.A.R. Labs and Dr. Stein gives Barry some important information about time travel.

In the The Nuclear Man, Joe and Cisco revisit the scene of Nora Allen's murder to dig up clues, which leads the to discover a splatter of blood, and the test results show that the blood actually belongs to Barry, more specifically an adult Barry Allen.

This implies that the other flash at the night of Nora Allen's murder was Barry himself.

Meanwhile, a new promo shows Joe asking Dr Wells if time travel is possible. He replies positively to the query.

The promo then shows Barry remembering the night of his mother's death, and says "15 years ago my mom was murdered".

The scene cuts to Barry looking at the 3D images of the red streak and muttering, "That's me," as Cisco says, "This is like some Twilight zone level stuff."

The promo then shows Joe saying, "You are going to change the past" to which Barry replies, "I won't make the same mistake twice."

The 30-second video ends with images teasing time travel.