After the tragic death of his close friend of crime boss Alexey Fomin, Pavel Semenov returned to service in the police and resumed the post of head of Department of criminal investigation internal Affairs on the Central district. His immediate supervisor is Lieutenant Colonel Andrey Mikhailov, who is tasked with restoring order not only in the Department itself, but also on the streets of the district, where criminal groups can not divide the spheres of influence.

At the same time, retired police Colonel Yevgeny Arsenyev is trying to throw off his long-time enemy General Lyubimov. And the former wife of Semenov Yulia suddenly becomes the owner of a multimillion-dollar inheritance, which was bequeathed to her by Alexey Fomin.

When a number of mysterious murders occur in the city, detectives put forward a version that a professional killer named the Architect, who was considered dead, returned to the city and personally liquidates the criminals who managed to avoid investigation and trial. To his horror, Andrey Mikhailov begins to suspect that Semyonov may have a direct connection to these murders. Mikhailov faces a difficult choice: to ignore his friendship with Semyonov and let his colleagues arrest him, or to allow Pavel to continue to do justice by illegal methods.