Vaishali is a dubbed version of tamil thriller movie "Eeram".In which, movie opens with water over flowing from a flat in E-block which is seen by the apartment watchman. When he goes to the flat to stop water he witnesses a young woman Sindhu Menon, who had died in drowned condition.
Eventually the investigation of the death is taking place which is done by an officer Aadhi, who is also the ex-lover of Sindhu Menon. Though the circumstantial evidence claims it as a suicide, Aadhi doubts it is not a suicide and starts to investigate in other angle.
He enquires Nandaa, Sindhu Menon’s husband and several other neighbours. However, he is yet to make progress in the case. An interesting flashback reveals that Aadhi and Sindhu Menon were lovers in Trichy. Rest of the story is deals with why they split and who is behind the murder of Sindhu Menon?