The Kid Detective (2020) on Netflix

Plot summary

Abe Applebaum was a celebrated child detective in Willowbrook, solving small mysteries for the town's residents. At twelve, his friend Gracie Gulliver vanished, and neither he nor the police could find her. Now 32, he still runs his detective agency, mocked by his peers and worried over by his parents, and he drinks and takes drugs to cope. Caroline, an orphaned high school student, hires him to investigate the murder of her boyfriend, Patrick Chang. Abe has never worked a murder case, sees a chance to prove himself, and takes it for free. His clumsy methods anger Patrick's father, and searching Patrick's life turns up secrets Caroline did not know.