Spoiler Alert: This article contains spoilers for Criminal Minds: Evolution season 3, episode 1.

Summary

Rossi discovers the weapon Voit used during the prison attack, leading to potential consequences.
Garcia's quirky empathy shines as she tries to see the salvageable in Voit, adding depth to her character.
The BAU team successfully saves victims, setting up a compelling storyline for upcoming episodes.

Criminal Minds: Evolution season 3, episode 1 arrived on Paramount+ on May 8th, 2025, and the beloved characters working for the BAU (Behavioral Analysis Unit) at the FBI are back in action. The intelligent team includes charming Luke Alvez (Adam Rodriguez), the prickly and tough David Rossi (Joe Mantegna), quirky researcher Penelope Garcia (Kirsten Vangness), and determined Emily Prentiss (Paget Brewster). Viewers also got the chance to catch up with Dr. Tara Lewis (Aisha Tyler), who is always one step ahead, and new trainee Tyler Green (Ryan-James Hatanaka).

Criminal Minds has always had talented guest stars such as Tim Curry, and the season 3 premiere (also referred to as Criminal Minds season 18) is as well-crafted and unsettling as ever. So, how does "Swimmer's Calculus" end, and what could happen next?

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By Aya Tsintziras

What Happens At The End Of Criminal Minds: Evolution Season 3, Episode 1, "Swimmer's Calculus"?

Emily Prentiss (Paget Brewster) on Criminal Minds: Evolution

At the end of Criminal Minds: Evolution season 3, episode 1, David Rossi tells Emily Prentiss he figured out the weapon that Elias Voit used during his prison attack: a shank created from a fan's wire cover. Rossi says Voit told him when he said he had a fan. Prentiss says that while Voit had been using his birth name Lee Duval while in prison, someone figured it out.

Then, Luke Alvez asks Penelope Garcia how she can sit next to Voit while he's in a coma. Garcia explains that when the BAU team was with Voit previously, she noticed something about him. Garcia is a quirky, whimsical, and perceptive character, and a scene like this one is a reminder why shows like Criminal Minds are so memorable. Garcia says:

"I looked in his eyes. I mean, I looked deep in there and I saw... Stuff. A soul."

Garcia says she's aware Voit is a "psychopath" but continues:

"I'm hoping I can see something salvageable in him."

In one of the rare humorous moments in the episode, Alvez says Garcia gives him heartburn, and she jokes about having "freakish empathy." This funny and clever scene proves why Alvez and Garcia are two of the most interesting Criminal Minds characters. She then shares her research on the main case of the episode: an unsub killer who targets users of a beach vacation website rental, finds them at the beach, then forces them to tread water in his backyard pool until they drown. Garcia looks into two leads: custom pools created in Chesapeake Bay and drowning-related incidents in the same area. The BAU team thinks that the killer was involved in a traumatic water-related incident that set him on this dark path.

Mom and daughter Kristi (Jade Estes) and Vivian (Tate Moore) are still treading water in the killer's pool and trying to survive. Earlier, the killer shot and killed Curtis (Eddie Estes), their husband and father, in front of them, which is one of the more emotional moments from Criminal Minds: Evolution season 3, episode 1. The BAU team figures out that the killer targeted the family because he had traumatic memories of his childhood. When Franklin Fowler (Sam O'Byrne) was ten, his sister, mom, and dad drowned, and he was the suspect.

The BAU team shows up at Franklin's house, and he shoots himself. The team saves Vivian and Kristi. Criminal Minds: Evolution season 3, episode 1 ends with some big news: trainee Tyler Green learns he has been assigned to Mobile, Alabama. Tyler says he's sad to leave the BAU and is surprised to find out he can't join the BAU for another ten years. Finally, Rossi continues to have trouble proving that he didn't order the prison attack on Voit. This is a powerful storyline as the internal affairs investigation could mean he loses his job, which puts Rossi in a rare vulnerable position. Similar to Hank Voight (Jason Beghe) on Chicago P.D. And Leroy Gibbs (Mark Harmon) on NCIS, Rossi is determined to catch dangerous criminals.

Prentiss shares that Franklin said, "this was part of the plan all along," and took videos of his victims in the pool. Finally, in a surprising reveal, Voit wakes up at the end of the episode.

Criminal Minds: Evolution Season 3, Episode 1 Sets Up A Shocking Season

Elias Voit (Zach Gilford) on Criminal Minds: Evolution

Although Elias Voit is in a coma for most of Criminal Minds: Evolution season 3, episode 1, he's still a main focus for the BAU team. While all the main characters have a stake in catching Voit for good and stopping the team of unsubs, David Rossi and Voit have a unique dynamic. After "Swimmer's Calculus," the focus for the upcoming season is clear: Rossi will keep trying to clear his name and take Voit down.

Why Is Criminal Minds: Evolution Season 3, Episode 1 Called "Swimmer's Calculus"?

The unsub's victims' teeth turn brown
this is called "swimmer's calculus" and happens because of chroline
this helps the team realize the killer is drowning people in pools, not the ocean

Fans can watch every new episode of Criminal Minds: Evolution season 3 on Thursdays on Paramount+ in May, June, and July 2025. Besides seeing more of Voit and hopefully learning more about the unsub network, fans can also get excited about the return of Spencer Reid (Matthew Gray Gubler) in an upcoming episode.

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Release Date: September 22, 2005
Network: CBS, Paramount+
Showrunner: Erica Messer
Directors: Félix Enríquez Alcalá, Rob Bailey, Matthew Gray Gubler, Joe Mantegna, John Gallagher, Douglas Aarniokoski, Guy Norman Bee, Larry Teng, Nelson McCormick, Alec Smight, Charles S. Carroll, Rob Spera, Charles Haid, Diana Valentine, Rob Hardy, Tawnia McKiernan, Bethany Rooney, Karen Gaviola, Sharat Raju, Thomas Gibson, Aisha Tyler, Anna Foerster, Gloria Muzio, John Terlesky
Writers: Bruce Zimmerman, Virgil Williams, Edward Allen Bernero, Janine Sherman Barrois, Chris Mundy, Simon Mirren, Debra J. Fisher, Kimberly A. Harrison, Jay Beattie, Dan Dworkin, Karen Maser, Oanh Ly, Stephanie Sengupta, Aaron Zelman, Kirsten Vangsness, Erica Meredith, Andi Bushell, Holly Harold, Alicia Kirk, Jeff Davis, Randy Huggins, Edward Napier, Jayne A. Archer, Chikodili Agwuna