Detective Pikachu Returns is an adventure game developed by Creatures and published by The Pokémon Company and Nintendo for the Nintendo Switch. First announced during a press release in 2019 alongside apps such as Pokémon Home, it is a sequel to 2016's Detective Pikachu for the Nintendo 3DS. It was showcased for the first time during a Nintendo Direct in June 2023, and was released on October 6, 2023.

Plot

Two years following the R incident, Tim Goodman and his partner Detective Pikachu continue to serve Ryme City as detectives. A ceremony where Mayor Howard Myers is honoring them with medals as a reward for their efforts is interrupted by a rampaging Corviknight. Tim and Pikachu investigate the chaos caused by Corviknight and recover Pikachu's signature hat, which the Corviknight had stolen, before returning to the ceremony.

The next day, Tim and Pikachu's services are enlisted by Inspector Frank Holiday to assist the police with an investigation at Sanjeev Denis's mansion, where the legendary Aurora Drop, a precious jewel, has gone missing. Mr. Denis's butler, Brandon Barnes, has been accused of the crime and is the police's top suspect, but Mr. Denis is convinced of his butler's innocence and requests Tim's help in finding the real culprit. By questioning Mr. Denis, Mr. Barnes, Mr. Denis's wife Claudia Denis, and new staff member Larry Turner, Tim and Pikachu are able to find enough evidence to prove Mr. Barnes is innocent and enlist the assistance of Mr. Denis's partner Growlithe, who possesses a powerful sense of smell, to track the real culprit. During the investigation, they run into Tim's classmate Rachel Myers, the daughter of Mayor Myers, and her friend Jessica Miller. Rachel requests Tim's help with something that she does not want to disclose in public, so Tim invites her to visit his apartment later that evening. They also briefly encounter an oddly behaving scientist named Charles Merloch, who performs a brief health exam on Pikachu. Tim and Pikachu are able to deduce and prove to the police that the real culprit was Larry Turner, who's working with an unknown accomplice, and that the Aurora Drop had been swallowed by Turner's partner, Cramorant. Although Cramorant initially spits up the jewel and Turner is taken into custody, a mysterious cube on Cramorant's back suddenly activates and the Gulp Pokémon swallows the Aurora Drop and escapes, though Turner insists he had no role in Cramorant's escape.

Tim and Pikachu return home, where Tim's mother, Irene Goodman, and sister, Sophia Goodman, are visiting for Tim's medal ceremony. Rachel arrives and is invited by Irene to join them for dinner, during which Pikachu falls mysteriously unconscious and sees memories of Tim's father, Harry Goodman, informing Irene that he wants a divorce. When Pikachu awakens, Tim and Rachel are relieved to see he is alright, and Rachel expresses that spending time with Tim and his family has relieved the concerns she had and she no longer feels the need to talk about what was bothering her. Instead, Tim asks if she knows anyone who may know more about the Aurora Drop, and Rachel suggests that they meet with her professor Trevor Gordon, who's an expert on minerals, the next day.

Tim, Pikachu, and Rachel head to the Southern Ruins, which Professor Gordon is investigating, but only find from his assistant, Chris Honor, that the professor had disappeared into the ruins days ago and never returned. Additionally, the ruins and their surrounding area have been mysteriously covered in ice and snow. Tim and Pikachu apply their detective skills to solve the ruins' puzzles and get inside to find Professor Gordon, with the assistance of the professor's Slowpoke and other local Pokémon. They encounter a Galarian Darmanitan on a rampage and sneak past it, eventually placating it with Slowpoke's tail as a snack. Darmanitan reveals that it, alongside several of its Ice-type friends, were kidnapped by a mysterious group and escaped, covering the ruins in ice to make it feel more like home. Pikachu and Darmanitan team up to navigate the ruins, using Darmanitan's strength to break rocks and find Darmanitan's missing friends and Professor Gordon, but the main entrance to the ruins closes behind them, trapping them all inside. Using Professor Gordon's knowledge and the Ice-type powers of Darmanitan's friend Eiscue, Tim and Pikachu are able to deduce the solution to the final puzzle and open a second entrance, allowing the group to escape the ruins. However, as they leave, they hear a mysterious man approaching, who attempts to steal Pikachu before fleeing. Darmanitan, Pikachu, and Eiscue pursue him and are attacked by a Mamoswine with the same kind of cube that Cramorant had; Darmanitan defeats the Mamoswine, but the man escapes. Tim asks Professor Gordon about the Aurora Drop, and the professor reveals that it is believed to be the dormant form of an extraterrestrial Pokémon.

On their way home, Tim, Pikachu, and Rachel see Mewtwo escaping from a swarm of Beedrill and carrying Harry's unconscious body. The Beedrill's attacks knock Mewtwo into the city, causing the residents to flee in a panic, and Harry's body is taken by mysterious men who fly away on the Beedrill. Pikachu attempts to ask Mewtwo what is going on, but the residents of Ryme City express fear of Genetic Pokémon and Mewtwo leaves to avoid further issues.

Before Tim and Pikachu can further investigate the Aurora Drop and the mysterious group that attacked them and took Harry, Pikachu is arrested by Brad McMaster for allegedly destroying a Slowpoke fountain. To prove Pikachu's innocence, Tim and Pikachu are forced to work separately, as Tim works with Rachel to investigate the destruction of the fountain and Pikachu questions the many other Pokémon who have been detained, sharing their findings during the detention center's brief visitation hours. While in custody, Pikachu and the other detained Pokémon are given the same mysterious cube devices used by the men that attacked them, and Pikachu learns it is used to control Pokémon's actions. Tim and Rachel are able to find evidence suggesting all of the detained Pokémon were framed, while Pikachu allies with a Luxray to sneak around the detention center and gets into the office of Will Butler, the chief of the Pokémon Protection Bureau, where he discovers a detained Ditto and papers suggesting Chief Butler is being paid to wrongfully detain Pokémon by an organization known as Unitas. Tim allies with Brad, who has become equally suspicious of the increase in arrests, and confronts Chief Butler as Pikachu and Luxray break out of the detention center with the other Pokémon. Tim is able to prove that the crimes were committed by Ditto, transformed into the other Pokémon and controlled through the cube on its back by Chief Butler. Brad arrests Butler and frees the Pokémon, but the device Butler used to control the Pokémon is remotely destroyed before they can take a closer look at it. Pikachu shows Tim another file he found in Butler's office, suggesting that Unitas is planning to target Jessica next. Worried for their friend, Tim, Rachel, and Pikachu decide to seek Jessica out the next morning, after wrapping up the loose ends on the current case.

As Tim prepares dinner, Irene drops a wedding ring, which is picked up by Pikachu, triggering another flashback that reveals Harry only requested a divorce from Irene to protect her. When Pikachu recovers, he sees Irene telling Tim and Sophia that Harry had not taken his wedding ring with him when he disappeared, but that she is confident he did not truly want a divorce and there must have been something else going on.

The next morning, Tim, Rachel, and Pikachu head to Bamboo Borough to check in on Jessica, but arrive before Unitas and join Jessica on a trip into the Bamboo Forest to acquire charcoal for the pizzeria she works for. During their trek into the forest, Pikachu is plagued by repeated flashbacks of Harry investigating the R incident in the same place, which is where he originally met and became partners with Pikachu. As Pikachu recounts these memories to Tim, he becomes repeatedly mixed up between actions taken by Harry and actions taken by Pikachu, piquing Tim's suspicions that something deeper is going on. In the present, Tim and Pikachu are joined by the Pangoro that was Pikachu's cellmate in the detention center, who Pikachu now remembers was his old friend Pancham while he still lived in the Bamboo Forest. When Rachel and Jessica disappear, Tim and Pikachu enlist Pangoro's strength to help them navigate the forest, eventually coming upon their friends held captive by another mysterious man controlling a Golem. Pangoro and Pikachu defeat the Golem and free it from the cube controlling it, allowing it to chase its former controller out of the forest, but Jessica reveals the man, a member of Unitas, has already taken what he came for: a thumbdrive containing research from Rachel's mother, Emma, which she had given to Jessica for safe-keeping out of fear it could be used to harm people and Pokémon. The research suggests a way that it would be possible for a person and Pokémon's consciousness to be combined.

After confirming that Rachel and Jessica are safe, Tim confronts Pikachu about the inconsistencies in his memories about Harry. Together, they conclude that Pikachu's body contains both Pikachu and Harry's consciousnesses. Pikachu is able to recall that, after Harry's car accident, Harry was slowly fading, but Pikachu was able to convince Mewtwo to do something to save him. Mewtwo was able to preserve Harry's consciousness in Pikachu's body, but to prevent Pikachu's own consciousness from being erased, it was forced to keep Harry's memories hidden away. Tim and Pikachu agree to investigate Unitas and try to return Harry to his own body.

Tim, Pikachu, and Rachel arrive at Unitas's facility at the Pokémon Unity Lab, which had been supposedly closed down following a berserk Pokémon rampage caused by R that resulted in Emma's death, and begin an infiltration, assisted by their friends Growlithe, Darmanitan, Luxray, and Pangoro. As they navigate the floors into the deepest basement, they steadily uncover Unitas's motivations behind the taking of the Aurora Drop, the attack on the ruins, the detainment of the innocent Pokémon, and the attack on Jessica, as well as the fact that Unitas is being led by Mayor Myers and Charles Merloch. Learning that Mayor Myers was motivated by his desire to protect Rachel after her mother's death, Tim and Rachel realize that Merloch has been manipulating him to achieve his own goals, which involve using Rachel's mother's research, as well as Harry and Pikachu, to combine his own consciousness with that of a Pokémon. Tim, Pikachu, and Rachel confront Mayor Myers and Merloch on the bottom floor, where they lay out the evidence of Merloch's wrongdoings to Mayor Myers, convincing him that he has been used. However, it is too late, as Merloch is able to awaken the Aurora Drop, revealing its true form of Deoxys, and take over Deoxys's body. Mewtwo arrives to fight off Merloch in Deoxys's body and prevent him from escaping while Tim and Pikachu attempt to deactivate the machine and undo the fusion. While the machine is stopped, the fusion persists. As such, Pikachu takes energy capsules containing energy extracted from his and Harry's bodies and smashes into Deoxys with them, returning Merloch to his own body and Deoxys back to its Aurora Drop form. However, Pikachu is worn out by this effort and is forced to stay behind as the facility collapses, leaving Tim, Rachel, and Mayor Myers to escape without him. Tim is distraught over losing his father once again, only to see Harry and Pikachu emerge from the wreckage, back in their own bodies and with Merloch ready to be taken into custody. Rachel and her father reconcile and Harry is reunited with his family as Merloch's machinations are put to an end.