The book "In deep swamps" by the Finnish writer Maria Salmela is a fascinating story about the adventures of three children who accidentally fall into mysterious swamps deep in the forest. The main characters are brave friends who together decide to explore the secrets of an ancient abandoned farm located near the swamps. However, what starts as a fun expedition quickly turns into a dangerous adventure when the kids realize that they are not alone. "In the deep swamps" is an exciting read that reveals the dark secrets of the past and tests the friendship and courage of the heroes.