Billy Green (Adam Pally) returns to his hometown of Valley Stream, New York, where he was the most popular kid in high school. Shortly after he arrives, the old woman across the street dies in her sleep. Billy thinks she was murdered by her son, former unpopular kid Lowell Shapiro (Vincent Kartheiser), and investigates with the help of his best friend Duane Douscher (Doug Mand).
Not to be mistaken with Most Likely to Die a 2015 Slasher Movie.
Most Likely to Murder contains examples of:
- Bait-and-Switch Accusation: Billy goes to the pharmacy where Lowell works to spy on him. Lowell catches Billy and says, "I know why you're here." Billy panics until Lowell continues, "You know, a lot of people have a hard time admitting that they need help with smoking. It's okay. You're here for the Habitrol patch, aren't you?"
- Basement-Dweller: Duane lives with his parents and sister, despite working as a realtor. Lowell also lived with his mother before her death.
- Batter Up!: Billy attempts to smash down Lowell's door with a baseball bat. Instead, the bat breaks in two, and Billy's wrist is injured.
- Disappeared Dad: Lowell's father, from whom he got his last name, left when he was a baby. As an adult, Lowell changes his name to his mother's maiden name, Crane.
- Glory Days: In the early 2000s, Billy was a football player known as the King of Valley Stream. Now he works a literally shitty job as a restroom attendant at a Las Vegas nightclub and is so out of shape he gets winded from running across the street.
- Heel Realization: Most of the townspeople have realized that they were assholes in high school. They look down on Billy for being the same old jerk. By the end, Billy realizes how awful he's been, especially to Lowell, whom he's hated since sixth grade for being "creepy" even though he hadn't done anything wrong.
- Home Porn Movie: Billy has a videotape from 2002 starring himself, his then-girlfriend Elana (Rebecca Naomi Jones), and various condiments. Elana's husband, the sheriff Jason Perkins (John Reynolds), is haunted by the existence of the tape. When he finally gets his hands on the tape, he plays it on a TV and his so horrified by what he sees that he flings the TV to the ground, stomps on it, and rips the tape out of the cassette.
- Impairment Shot: When Billy is drunk, everything is blurred and the lights look like rainbows.
- I Need a Freaking Drink: When Billy finds out that his ex Kara Doblowski (Rachel Bloom) is now dating Lowell, he says, "I'm gonna need a lot of drinks."
- Mercy Kill: Lowell killed his mother on her request. Her Parkinson's disease had progressed to the point where she couldn't walk or feed herself, and she didn't want to be dependent on others.
- My Beloved Smother: Lowell was accepted into Stanford, but his mother wouldn't let him go because she wanted to keep him around.
- My God, You Are Serious!: When Billy tells people Lowell is a murderer, most of them assume he's playing one of the morbid pranks he was fond of in high school. Inverted in the climax, when Billy claims that I Was Joking to keep Lowell out of jail.
- My Sister Is Off-Limits: Duane repeatedly tells Billy not to go near his younger sister Tami (Julia Goldani Telles). When Billy tries to kiss Tami under the mistaken impression that she's interested, Duane is enraged and temporarily ends their friendship.
- Naughty Birdwatching: Billy watches Lowell's window through binoculars in the early morning, hoping to see him having sex with Kara. Instead he sees him screaming, then going outside to throw something out. The next morning Lowell tells the police he was asleep at that time, causing Billy to become suspicious.
- Porn Stash: At the bottom of a drawer in Billy's childhood bedroom is an issue of Hustler, as well as the sex tape of him and Elana.
- Self-Harm: Billy thinks the scratches on Lowell's arm were from his mother while he was killing her, but really they were self-inflicted, to deal with the stress of her death.
- Sex for Solace: Kara reminds Billy that the last time they had sex was after Hurricane Sandy, when she was upset about the loss of her childhood photos.
- Special Thanks: Special thanks to a long list of people and organizations, and a very special thanks to the New York City Mayor's Office of Film, Television, and Broadcasting.
- The Stinger: There's a mid-credits scene of Sheriff Perkins in the car, receiving a phone call from Elana about how their son ate weed that he found in a bobblehead dog that Perkins stole from Billy.
- String Theory: Billy and Duane hang up incriminating evidence about Lowell on red strings.
