Will Trent Season 3 Episode 7 Review: Why "Mariachi Shelly's Frankenstein" Is the Best Episode of the Series' Run

Every once in a while, a TV procedural delivers an episode so tightly created, so emotionally resonant, and so purely thrilling that it redefines what the show is capable of. For ABC's Will Trent, that episode is Season 3 Episode 7, "Mariachi Shelly's Frankenstein."

What Is Will Trent Season 3 Episode 7 About?

Titled "Mariachi Shelly's Frankenstein," the episode picks up directly from the Season 3 Episode 6 cliffhanger in which APD Detective Angie Polaski (Erika Christensen) concludes that John Shelley, the man convicted of a brutal assault and murder more than 20 years ago,  is not the real perpetrator. The original crime involved a young woman named Alice Finney, whose killer left a disturbing signature: the victim's tongue was cut out. When Angie notices that Peggy Higgins, a newly discovered murder victim, was killed in the same fashion, the evidence points to a copycat, or worse, the real killer who has been free for two decades.

To make matters more urgent, a tropical storm has locked down the GBI and APD offices, trapping everyone inside, including, it turns out, the killer. Special Agent Will Trent (Ramón Rodríguez) and Angie must race against time in a dark building to identify and stop a murderer who is hiding in plain sight among colleagues.

The Locked-Room Formula Done Perfectly

What separates "Mariachi Shelly's Frankenstein" from virtually every other episode of Will Trent is its use of setting to drive the narrative home. The storm doesn't just provide the perfect atmosphere; it transforms the GBI building into this insane pressure cooker. The confined space also amplifies tension and forces all the characters together in a very unexpected setting, which sort of strips away the procedural's usual freedom to work across the city.

The storm also gives the episode a different aura visually. The flickering lights, the rain, and the constant awareness that no one can simply leave create a paranoid feel that makes Will Trent feel like some kind of thriller film. It's the kind of television that makes you forget your real life surrounding.

Will and Angie: A Partnership Reborn

One of Season 3's ongoing threads has been the careful, sometimes painful, on-and-off rollercoaster of the relationship between Will and Angie. After agreeing in Episode 4 to be nothing more than casual coworkers, the storm forces them into proximity and genuine interdependence. "Mariachi Shelly's Frankenstein" gives Ramón Rodríguez and Erika Christensen one of the best chemistry opportunities they have shared since the show began.

While their dynamic here isn't romantic, it still carries a rich and even more  complicated weight. Watching them work a case together, slipping back into the groove of their complicated partnership, is so satisfying.

Pete and Caroline: The Episode's Surprise Emotional Core

If Will and Angie are the icing on the cake of "Mariachi Shelly's Frankenstein," Pete Chin and Caroline are the unexpected heart of this episode. For most of the show, these two characters have been likable backgroundcharacters. Episode 7 changes that completely.

When Caroline is found seriously injured, Pete, the GBI's mortuary specialist, is the only medical option available. The problem: Pete is trained to work on the dead, not the living. The episode uses this premise to excavate something genuinely moving from a character we thought we knew. We learn that Pete was once a practicing surgeon and that a tragic death involving a patient drove him to his present career in the mortuary. As he works to keep Caroline alive, the character goes from a supporting player into someone we are deeply invested in.

It is a masterclass in what good ensemble writing can accomplish.

The Supporting Cast Gets Its Moment

One hallmark of a truly great ensemble episode is the sense that no one is wasted. "Mariachi Shelly's Frankenstein" earns that distinction across the board. Amanda Wagner (Sonja Sohn), typically the show's authority figure, gets to display genuine vulnerability as she ensures Caroline’s life is saved. Faith Mitchell (Iantha Richardson) has a standout physical moment in which she becomes the decisive piece in a tense rescue effort. Even Ormewood (Jake McLaughlin), Franklin (Kevin Daniels), and Captain Heller provide a rare moment of comic relief, their stairway Mariachi jokes are the highlight of the episode, and it shows that a bond exists among the characters of Will Trent.

Gina Rodriguez, who joined the cast as ADA Marion Alba for Season 3, also gets meaningful screen time as the killer's attention turns toward her. This allows the episode to function simultaneously as a case-of-the-week thriller and a season arc episode.

The Serial Killer Reveal: Obvious But Effective

Any honest review of "Mariachi Shelly's Frankenstein" must acknowledge that attentive viewers will likely identify the killer before the formal reveal. The clues were laid in the episode. There is a reference to attending school near John Shelley, a changed appearance, all of which points clearly enough in one direction.

But here is where the episode demonstrates sophisticated storytelling instincts: an obvious killer does not make for a less thrilling episode. The tension does not live in the mystery of who; it lives in the question of when and whether the team will stop them in time. With everyone trapped in the building, with Caroline fighting for her life, and with Marion directly threatened, the stakes are viscerally real regardless of who the audience suspects. The reveal lands hard, not because it surprises, but because by that point, the show has made you care enormously about the people at risk.

Why Episode 7 Stands Among the Best in the Series' Run

Let's put "Mariachi Shelly's Frankenstein" in context. Will Trent premiered in January 2023 and earned an 89% approval rating on Rotten Tomatoes for its first season, praised by critics as an above-average broadcast procedural. Season 3 debuted on January 7, 2025, introduced Gina Rodriguez as a series regular, and continued the show's upward creative trajectory. Episode 7 sits at a 6.9 rating on tracking platforms  notably the highest-rated episode of Season 3.

Where to Watch Will Trent Season 3 Episode 7

"Mariachi Shelly's Frankenstein" originally aired on ABC on February 18, 2025. The episode is available to stream on Hulu and on the ABC website. Will Trent Season 3 is available in full for streaming, and with Season 4 having premiered in January 2026, there has never been a better time to catch up.

Frequently Asked Questions About Will Trent Season 3 Episode 7

What is the title of Will Trent Season 3 Episode 7?

The episode is titled "Mariachi Shelly's Frankenstein." It aired on Tuesday, February 18, 2025 on ABC.

Who is the serial killer in Will Trent Season 3 Episode 7?

The episode reveals that the real killer, responsible for a murder 20 years ago as well as recent crimes, is someone much closer to the investigation than initially suspected. Clues planted in Episode 6, including a reference to attending school near John Shelley, point toward the killer's identity before the formal reveal.

Is Will Trent Season 3 Episode 7 the best episode of the series?

Multiple critics and tracking platforms point to Episode 7 as the highest-rated episode of Season 3, and many reviewers describe it as one of the strongest episodes in the show's entire run. Its combination of locked-room tension, ensemble character work, and emotional storytelling makes it a standout installment.

Who stars in Will Trent Season 3?

Will Trent Season 3 stars Ramón Rodríguez as Special Agent Will Trent, Erika Christensen as Angie Polaski, Iantha Richardson as Faith Mitchell, Jake McLaughlin as Michael Ormewood, Sonja Sohn as Amanda Wagner, and Gina Rodriguez as ADA Marion Alba, who joined as a series regular for Season 3.

Is Will Trent based on a book?

Yes. Will Trent is based on the bestselling novel series by Karin Slaughter, who also serves as an executive producer on the ABC television adaptation. The show premiered in January 2023 and has been renewed through Season 4.

Final Verdict

Will Trent Season 3 Episode 7 — "Mariachi Shelly's Frankenstein" is a masterfully crafted hour of television that justifies every superlative thrown at it. It takes the raw materials of a network procedural and, through smart writing, confident direction, and extraordinary ensemble performance, transforms them into something genuinely cinematic. It knows when to generate dread and when to let in light. It gives its most underserved characters their due. It makes you feel the stakes.

If you have been sleeping on Will Trent, Episode 7 of Season 3 is the argument for why you should start watching. And if you're already a fan, this is the episode you will be citing when you try to convince someone else to give the show a chance.