Psychologist Sean Rooney spent nine formative months as a trainee in Hillwood Mental Hospital, aka, the Castle. Rooney has a particular reason for choosing the Castle as his placement as the Castle has many secrets. Long-term patients are mysteriously killing themselves. The hospital management team consider suicide in large mental hospitals as coming ‘with the turf’, but Rooney doesn’t agree and believes there is more to these suicides. Rooney forms a self-help patient group to investigate the mysterious deaths. The Castle doesn’t give up its secrets easily whether they be historical, criminal, or supernatural. It takes a group of likeminded patients to discover what is really going on.