Geologist Lena while on her way to Antarctica learns about the disappearance of her daughter, whom she has not seen for seven years. Ada disappeared with a group of preschoolers. Rafal, Lena's old school friend, leads the police operation.

Lena sees visions and begins to search for the meaning of the strange symbol. She follows the trail of two of Ada's friends who are secretly exploring the Wałbrzych underground.

The police find the German who paid Ada to search for German treasures. In the meantime, another child disappears in Wałbrzych. Some of the locals start accusing the local Roma of kidnapping.

Lena convinces the police to send cavers to comb the former German underground complex. She starts searching for the address from the key found on Schnirel, who is taken to jail.

Led by a vision, Lena goes to the Wałbrzych Mausoleum, where she finds a secret passage to underground tunnels. She comes across a secret laboratory and loses consciousness.

Two missing children emerge from the tunnel, with severe hypothermia. Czarnecka immediately takes care of them and blocks access to them. Trying to find out more, Lena visits Tymek, Ada's friend, in the hospital.