Ace detective Harry Goodman goes mysteriously missing, prompting his 21-year-old son, Tim, to find out what happened. Aiding in the investigation is Harry's former Pokémon partner, wise-cracking, adorable super-sleuth Detective Pikachu. Finding that they are uniquely equipped to work together, as Tim is the only human who can talk with Pikachu, they join forces to unravel the tangled mystery.