The Flash's hit first season is winding down, with only four episodes left to go. The CW has released a new trailer that teases these final episodes, which culminate with Barry Allen (Grant Gustin) squaring off against the man who killed his mother all those years ago, Reverse Flash, a.k.a. Harrison Wells (Tom Cavanagh). Harrison has been Barry's mentor for all of Season 1, but now Allen must seek revenge for his mother's death. This trailer also teases that Carlos Valdes' Cisco Ramon may be in grave danger, and it's possible that he could transform into Vibe, like Cisco does in the original comics.

Next week's episode, "The Trap", centers on Barry, Caitlin (Danielle Panabaker), Cisco and Joe (Jesse L. Martin) setting a trap for Wells. Cisco uses himself as prey which puts him in grave danger. Meanwhile, Eddie (Rick Cosnett) makes a decision regarding Iris (Candice Patton), which leaves Joe a bit unsettled.

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That episode is then followed by "Grodd Lives" on Tuesday, May 5, where Barry must deal with the Reverse Flash's latest threat to a member of the group. To make matter worse, Dr. Wells unleashes Grodd on the city in order to distract Barry and the team. Joe, Barry and Cisco head down into the sewers to catch Grodd but the gorilla quickly gets the upper hand after he kidnaps Joe. Iris and Barry have a heart to heart talk. Unfortunately, we don't have any details on the last two episodes yet, but check out the trailer below, and stay tuned for more as The Flash's first season comes to a close over the next few weeks.