Set in the fictional dystopian city-state of Khansaar, the film follows the friendship between Deva, a tribesman, and Varadha, the prince of Khansaar. When a coup d'état is planned by his father's ministers and his relatives, Varadha enlists Deva's help to become Khansaar's undisputed ruler.

Asthram is a gripping crime thriller that delves into a series of puzzling suicides, where victims are found stabbed under eerily similar circumstances. Determined to uncover the truth, Inspector Akilan tasked himself to investigate the case. As the investigation unfolds, Akilan gathers crucial evidence that links each case, unraveling a web of secrets.