An undercover cop in a not-too-distant future becomes involved with a dangerous new drug and begins to lose his own identity as a result.

"A Scanner Darkly" is a 2006 sci-fi film based on the novel of the same name by Philip K. Dick. The story is set in a dystopian future where a powerful drug called "Substance D" has caused widespread addiction and the government has employed surveillance to combat it.

The film follows an undercover cop as he becomes increasingly entrenched in the drug world, leading to a loss of identity and reality. The film uses rotoscoping animation to create a unique visual style. It stars Keanu Reeves, Robert Downey Jr., and Woody Harrelson.