The precinct heads to Tactical Village Day, a mandatory training course in which all regional precincts compete. While there, Amy runs into Teddy, a fellow officer she used to date. Meanwhile, Holt becomes addicted to a game on his phone and Rosa is pissed at Charles for not inviting her to his wedding

Jake’s crushing debt finally catches up to him, and he is in danger of losing his apartment, unless Gina can find a way to bail him out. Captain Holt and Sergeant Jeffords hold performance reviews for the entire precinct, and Rosa and Boyle have a run-in with one of the weekend squad officers.

Detective Boyle’s new romance has upped his swagger, but Jake intervenes before his colleague goes “Full Boyle” and gets too serious, too soon, with his girlfriend. Meanwhile, Rosa and Amy have trouble taking a costumed citizen crime-fighter seriously, and Captain Holt has a new opponent

The officers in the precinct head over to Holt’s house to celebrate his birthday, but they wind up making a poor impression on his husband.

Jake probes a series of hotel robberies with Amy, but is upset when he learns she may leave the precinct to work with the Vulture in the Special Crimes unit. Meanwhile, Holt and Jeffords try to make their workplace more efficient.

On his first task back in the field, Terry busts a steroid ring, and in doing so, takes cues from Jake on how to harness his emotions. Meanwhile, Amy and Rosa help solve a breaking-and-entering case at Gina’s apartment.

Jake and Amy’s ongoing bet about who can make more arrests comes to a close. Meanwhile, Charles receives the Medal of Valor for getting shot in the line of duty, but the pain medication he is taking causes him to reveal his true opinions about his colleagues.

Jake is interested in one of Rosa’s perps, Doug Judy, who has information about the “Pontiac Bandit,” a car thief whom Jake has been tracking for years. Meanwhile, the station tries to accommodate a scooter-bound Charles’ every need when he returns to work, but he proves to be too much to handle. And Captain Holt struggles to find a home for two puppies.

When Holt starts getting death threats, Jake takes charge of his security; Amy tries to get a precinct Christmas photo; Terry gets his mojo back.

When Holt and Jake must leave Amy’s Thanksgiving dinner to catch a perp, Boyle steps in to save the day.

When Sal’s Pizza burns down, Jake goes out of his way to disprove the fire marshal’s assumption that the owner set the fire; a computer virus exposes the precinct members’ Internet browser histories.

Jake gets to spend the day with his hero, a former crime reporter; Terry and Charles work with Rosa on how she comes across on the witness stand.

When Jake makes an arrest without a lot of proof, he only has 48 hours to collect evidence, or else the “perp” will be released. After his unsuccessful interrogation of the suspect, Jake forces his co-workers to spend their weekend helping him crack the case. So, while the team is stuck at the precinct, Charles judges a pie contest between Gina and Rosa, and Holt helps Terry look better in the eyes of his in-laws.

It’s Halloween night, a busy time of the year for any police precinct. Amy detests the holiday, and is not thrilled when she has to don a costume to go undercover on street patrol with Charles. Back at the precinct, Jake bets Captain Holt that he can steal his Medal of Valor before midnight, which results in him bringing out some costumes of his own.

A detective from Major Crimes takes over Jake’s nearly solved murder case and steals his thunder.

Much to the team’s annoyance, Jake hits on an attractive medical examiner, Dr. Rossi at a crime scene and holds up the autopsy report. He learns his lesson when Dr. Rossi turns out to be more than he bargained for. Meanwhile, Amy’s purse-snatching case is stalled when the sketch artist is out sick, but she discovers that Sgt. Jeffords has hidden artistic talents.

When Jake starts accumulating unsolved cases, the other detectives worry his losing streak will rub off on them; Amy, Rosa and Gina run a program for at-risk youth; Boyle helps Sergeant Jeffords with a case.

When Jake is late for roll call, Captain Ray Holt assigns him to a graffiti case that Jake feels is below his level. However, when the culprit turns out to be the Deputy Commissioner’s son, the case becomes a major problem. Meanwhile, Gina’s psychic friend visits the precinct and gets inside Charles.

Detective Jake Peralta is a talented, but carefree police detective at Brooklyn’s 99th precinct who, along with his eclectic group of colleagues, are used to having a lax captain around the office. However, when tightly-wound Captain Ray Holt takes over, he is determined to make this dysfunctional group of detectives into the best precinct in Brooklyn.

Team Scorpion heads to Northeast Africa where they must carefully navigate a minefield in order to save the lives of local villagers. Also, Paige and Walter’s relationship takes a shocking turn, and Toby and Happy make an important decision.

Paige’s maternal side goes into high gear when Team Scorpion must save an unconscious, hypothermic boy stuck in the wheel well of their airborne airplane. Also, Walter’s white lie to Paige starts to take a toll on him, and Paige realizes something’s up.

Team Scorpion must use their high IQs to win a softball game when the homeland director challenges, with all of their future government contracts on the line. Also, Walter’s secret night out with Florence puts Toby and Happy on edge.

Team Scorpion heads to the bayou to track down a cagey alligator in order to stop a deadly mosquito-borne virus, and Paige teaches Walter the concept of the “white lie.” Also, Walter hits Cabe with a tranquilizer gun and Toby must save his life, and Sylvester and Ralph help Patty when the mean girls at her school force her to get a dreaded tardy slip.

Team Scorpion inadvertently crashes a bank robbery in progress and is taken hostage. Also, Sylvester’s feelings for Florence grow.

The geniuses of Team Scorpion turn into knuckleheads and Paige must simplify the science for them, when their mental faculties are impaired during a job to prevent the creation of a black hole. Also, Florence and Sylvester grow closer when she helps him with a special project.

On Valentine’s Day, Team Scorpion must set aside their romantic plans to help a doctor and pilot trapped inside a helicopter that crashed atop a skyscraper. Also, Toby and Happy wait for news on their fertility results, and Sylvester realizes that he may have feelings for Florence.

Team Scorpion must prevent an incoming tsunami from hitting a vulnerable nuclear power facility, and Toby secretly helps his ex-fiancée retrieve her stolen identity.

A solar storm knocks out power in Los Angeles, and Team Scorpion must help a teen pilot and his girlfriend who are lost over the Pacific without navigation or radio contact. Also, during the crisis, Walter must look after a group of Ralph’s classmates, and Cabe tries to tell Allie finally that he loves her.

Team Scorpion must work with Toby’s nemesis, Quincy Berkstead, and his wife, Amy, Toby’s ex-fiancée, when they are locked inside an artificially intelligent doomsday bunker that aims to kill them. Also, Walter is distracted by his recent dream where he is married to Florence, not Paige.

On Christmas Eve, when Walter chooses work over spending quality time with his friends, he falls down the stairs and hits his head, and as he lays unconscious, he enters a dream world where Team Scorpion never existed.

As Team Scorpion anxiously awaits the verdict of Cabe’s trial which could send him to prison, they focus their nervous energy on trying to save a dog stuck in a cistern.

As Cabe’s trial looms over Team Scorpion, a simple case goes sideways when they help a father and his daughter whose plane crashes nearby. Also, Paige helps Walter navigate his feelings about Cabe’s possible future in prison.

On Thanksgiving, Team Scorpion’s new neighbor, Florence, joins them at sea on a mission to destroy a floating island of trash, but her flawed contribution leaves her, Walter and Happy stranded on the quickly dissolving island. Also, Toby works with Cabe to uncover the details of his father’s death that he has suppressed since he was a boy.

For Sylvester’s birthday, Team Scorpion visits a renaissance festival, but the revelry is cut short when a group tries to rob a nearby police evidence locker. Also, Paige grows weary of Walter’s play-by-play of all the historical inaccuracies at the festival

While tracking a device that can prevent a nuclear meltdown through the Los Angeles sewers, Walter learns the nuances of listening and not offering advice to Paige. Also, Team Scorpion meets Florence, their new neighbor at the garage, after she sends a mix of smelly chemicals through their shared ventilation as a warning to keep the noise down.

At Halloween, Team Scorpion takes on a case to prove the existence of ghosts on the Queen Mary but find an all-too-real disaster when they locate a “ghost ship” on a deadly collision course. Also, Walter considers taking note of Paige’s interests to benefit their relationship.

While attending a tech convention, Team Scorpion is taken hostage by a group attempting a virtual heist.

While decommissioning an old nuclear missile, a simple accident causes Team Scorpion to endure exposure to toxic vapor while trying to prevent the nuke from detonating. Also, Paige confronts Happy about constantly tagging along with her and Walter.

When poachers almost kill a pregnant endangered deer, Team Scorpion recreates the animal’s womb to try to save it and its baby’s life. Also, Happy and Toby discuss the future of their family.

Team Scorpion continues to work with their nemesis, Mark Collins, in order to prevent an extinction event that could end humanity. Also, Cabe’s last-minute decision while on the case leads to the possible end of his career.