One morning, on her way to a meeting, Meenakshi witnesses a road accident that kills a young man. When the young man's mother, Chandana, tells her that it was no accident and asks her to investigate, Meenakshi initially refuses.

Meenakshi goes to Chandana's house and finds it turned upside down. Someone has obviously searched it so she decides to investigate. She learns from Chandana that her dead son, Partho, was a brilliant virology student.

When Dr Rakhaw takes Meenakshi to his personal laboratory, Meenakshi's cover as a virologist is quickly blown. Rakhaw nevertheless gives him a slide that he had in his laboratory.

The Ministry of Health's office organises a crisis meeting on the pig deaths and the three human victims at the farm. Meenakshi finds the pig farm in Barasat, but when she arrives, the farm is empty.