Thanatos Contract is the story of Virgil Birmire, a high school student in the town of Autumn Gray. After his father died in a car crash and his brother went into a coma from said crash, Virgil keeps himself locked into the online world of Shiniablo, a forum for the depressed and down-trodden. There he interacts with his only two friends, AnimeFan21 and Mistress Eternity.

One day, after Virgil's mother berates him for his choice in future, Mistress Eternity offers up the plan to meet up in real life. Why so sudden? Will they be able to get along as much as they do in Shiniablo? Thus begins the meeting of offline friends, a meeting that will turn out darker than Virgil expects...

At the end of the last episode of Thanatos Contract, Virgil hesitantly signed the contract presented by the illusive Mr. Smiles, a contract to kill Virgil's comatose twin brother, Victor. However, despite Virgil's efforts to help his brother find peace, Victor had already gotten out of his coma earlier that evening. Virgil's mother had tried to alert him over the phone, but he had ignorantly ignored her calls.

Feeling betrayed by Dominique, Virgil blamed her for the entire ordeal. She fleed from him in a fit of tears. Will the online friends be able to overcome their issues in order to save Victor in time, or will the complexity of their offline relationship prevent them from doing so? Thus the second act begins...

The concluding episode of Thanatos Contract. With the confrontration ending up a bust, time is ticking closer and closer to Victor Birmire's death. Will Virgil, Dominique, and AnimeFan21 be able to stop Mr. Smiles in time? Will they be able to solidfy their friendship in not only the online world but offline as well?