In the span of a day, where everything seems to flow at the ordinary pace of provincial life, the lives of a gas station attendant with obsessive-compulsive disorder, a woman with a gambling addiction, a teenager in a youth community, and his counselor intersect and are destined to change forever. Allison is a girl placed in a youth community after reporting her father for abuse. Matteo is a counselor in the youth community where Allison lives, deciding to take her under his wing in the hope of helping her build the peaceful future she deserves. Caterina is a woman with a 10-year-old son who, while trying in every way to recover the necessary money, finds herself taking dangerous shortcuts. Vincenzo manages a gas station on the highway and is a former alcoholic, suffering from obsessive-compulsive disorder. He spends his time enclosed in his booth listening to music and voice messages from his wife who passed away two years ago.
Osmosi is a film that narrates the stories of these four individuals who, within the span of a day, cross paths and touch each other's lives. Their encounter, like the collision of two chemical substances, will create a reaction from which they will all emerge transformed.