Ahead of tonight’s new episode, The Flash executive producer Andrew Kreisberg teases the final stretch of episodes for the season.

Last week’s episode of The Flash, “Who Is Harrison Wells?”, featured Joe and Cisco traveling to Starling City, where they discovered a set of remains that belonged to the real Harrison Wells. Meanwhile, Cisco began having dreams about the alternate timeline in which Wells killed him, and Eddie, now aware of Barry’s secret identity, revealed to Iris that he was working alongside the Flash.

Tonight’s episode, titled “The Trap,” sets off the final four episodes of the season, which are set to be game-changers. Moving forward, we’ll be looking at “Barry having enough information about Wells to realize that he can force a confession out of Wells — that he killed his mom and got his dad out of prison. That really becomes Barry’s overriding concern,” Kreisberg previews.

He adds, “Those people who thought that the events of episode 15, when the timeline was altered, was a full and total reset, and that those events didn’t matter, are going to be proven very wrong. It turns out that the key in getting Wells to confess lies is Cisco’s ability to remember that alternate timeline.”

Answers as to how Cisco is able to remember the alternate timeline will come later this season, Kreisberg promises.

Related: The Flash: Where are Cisco’s dreams coming from?

Kreisberg also teases upcoming interactions between Wells/Eobard Thawne and Eddie. “For those people who, just like Eddie, wondered why the Reverse Flash didn’t kill him in episode 9 when he killed every other cop in that room, you’re going to get the answer to that.”

Plus, “There’s definitely a confrontation between the Reverse Flash and Iris coming up, which is fairly exciting,” though Thawne won’t necessarily be as fixated on Iris as he is in the comics.

Why? “As always, we take our cue from the comics, but we don’t always necessarily follow the stories perfectly,” Kreisberg explains. “People always ask how closely will it align with the comics, but it’s not as simple as when you’re adapting Game of Thrones, where you’re following one story. With the comics, you’re following multiple stories with multiple writers. People are constantly retconned and revised, backstories are revised and motivations are changed. In some ways, it’s good for us because it allows us to cherry-pick the best parts that we feel work for us.”

Speaking of Iris, she is about to find out Barry’s secret. She’ll be furious with Barry and Joe, but perhaps surprisingly, not Eddie. “The reason she’s not pissed at Eddie will become apparent, which is kind of interesting,” Kreisberg previews.

“But she’s definitely pissed at Barry and Joe. Keeping people in the dark for their own protection is a trope for these shows. Sometimes, especially on Arrow, we let that go on for too long,” he admits. “We’re trying to correct that on this show. We’re definitely building toward Iris finding out in this first season, not just in the finale, and her having a reaction to it that’s quite normal.”

However, while there will be some anger, it won’t be forever. “As always with these things, there’s going to be emotional fallout — but it’ll end up bringing people closer together.”

So what happens with Iris knowing the truth at long last? “It’s funny because we read the comments and see some people are upset that Iris doesn’t know. For us, keeping this secret is the least interesting aspect of all of these shows. Especially on Arrow, there’s such a freedom to it now that everybody is in on this secret, everyone can just have real conversations. Everyone is on board, so everyone can be talking about everything that they should be talking about.”

He adds, “For now, it’s better that everybody knows and everybody can talk about it and be on the same page. The false jeopardy of ‘we have to keep this secret’ fades away, and it allows you to come up with more grounded, more organic problems for your characters to have to face.”

The Flash airs Tuesdays at 8:00 p.m. ET on The CW.

What do you want to see in the final episodes of ‘The Flash’ season 1?