Alyssum follows the story of a young woman named Alyssa - whose day to day life follows a borderline obsessive routine of spending, beauty routines and validation seeking through sex and hookup culture, despite the negative impacts it has on her life and mental state. One night whilst bathing, Alyssa scrubs too hard in a dissociative state, ripping her skin and revealing rotting flesh underneath. Naturally terrified, she tries to get rid of the rot and makes it worse before deciding to cover the wound with makeup in order to continue her lifestyle and quest for love. But the rot worsens, and Alyssa must face herself as her life takes a dark, surreal turn.