Set in 1950s England, ASYLUM, a tale of erotic obsession, tells the story of Stella Raphael (Natasha Richardson), a restless, beautiful woman who desperately desires to find in romantic love the one thing that will change everything.

When her husband Max (Hugh Bonneville), an ambitious forensic psychiatrist, is appointed Deputy Superintendent at a high-security psychiatric hospital for the criminally insane, Stella and her young son come with him to live on the grounds. Being in proximity of madness has a dangerous attraction for this woman; with its eerie, gothic beauty and endless echoing corridors, the institution itself seems to draw Stella in.

Then she meets inmate Edgar Stark (Marton Csokas), an artist confined for murdering his wife in a jealous rage. There is a visceral connection between the two. Stella finds release and a sense of herself reborn in Edgar's embrace. Senior physician Peter Cleave (Ian McKellen), long in line for the position to which Max has been promoted, watches carefully as Stella and Edgar bond - "sexual pathology" is his particular field of interest. The cunning Dr. Cleave is a master observer, one who especially prides himself on manipulation.

Stella is now the center of attention for three men, each of whom desires to possess her: the husband, the lover and the doctor. When Edgar escapes the asylum and their secret affair is revealed, Stella determines to continue on with her lover, no matter what the cost. What began as a fierce brave step towards freedom now threatens to bring Stella to other, even more intense forms of confinement. Having taken the risk, there is no turning back.