The promo for Riverdale Season 4, Episode 16, titled “The Locked Room,” reveals that Jughead and Betty Cooper (Lili Reinhart) will spend much of the episode explaining exactly how their plan unfolded over the last few episodes of The CW show.

At the start of the trailer, which first aired after the March 4 episode of Riverdale, we see Betty and Jughead arrive at Stonewall Prep, where a group of his classmates, including Donna Sweett (Sarah Desjardins) and Bret Weston Wallis (Sean Depner), are assembled.

As viewers of the most recent episode will know, Bret and Donna are the two people who tried to kill Jughead, so his return may cause the already unstable pair to lose it even further. However, in the trailer, Donna seems pretty cool, telling Jughead: “I knew you weren’t really dead.”

Jughead then begins to take his Stonewall classmates through how his plan worked. “Don’t worry, I’m going to take you through it step by step…the time-tested genre, the locked-room mystery.”

The title of Riverdale Season 4, Episode 16 (“The Locked Room”) and Jug’s use of the phrase in the preview give us our biggest hints yet as to how the faking of the death worked.

Writing in The Independent, The Black Lizard Big Book of Locked-Room Mysteries author Otto Penzler said of the genre: “The locked-room mystery, or impossible-crime story, is the ultimate manifestation of the cerebral detective story…What he demonstrates appears to be impossible…Yet we have just seen it happen, right before our very focused eyes.”

The first-ever locked-room mystery was Edgar Allan Poe’s The Murders in the Rue Morgue, and seeing as Jug is a big Poe fan, the plot of this story could give fans a clue. As that story includes an angry orangutan, expect a typically outlandish explanation from Betty and Jughead, perhaps to do with Jughead’s research into the perfect murder earlier this season.

The end of the promo and the episode synopsis, however, give some hints that not all might be as it seems. The Riverdale Season 4, Episode 16 synopsis reads: “After Jughead’s resurrection, Betty, Archie (K.J. Apa), and Veronica (Camila Mendes) notice that there’s something different about him.”

Betty also suggests something strange is afoot. At the end of the trailer to “The Locked Room,” we hear her say “…but there’s a twist.”

Riverdale Season 4, Episode 16 is released on Wednesday, March 11, at 8 p.m. ET / 7 p.m. CT, on The CW and the following day on Netflix internationally.