The folks at Super Bro Movies have revealed the official synopsis for the upcoming Pokémon Detective Pikachu film:
The story begins when ace private eye 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, Detective Pikachu: a hilariously wise-cracking, adorable super-sleuth who is a puzzlement even to himself. Finding that they are uniquely equipped to communicate with one another, Tim and Pikachu become reluctant partners on a thrilling adventure to unravel the tangled mystery. Chasing clues together through the neon-lit streets of Ryme City—a sprawling, modern metropolis where humans and Pokémon live in partnership in a hyper-realistic live-action world—they encounter a diverse cast of Pokémon characters and uncover a shocking plot that could destroy this peaceful co-existence and threaten the whole Pokémon universe.
Source: Super Bro Movies