Could dinosaurs get used to the presence of humans? Today we know they were far more intelligent than presumed. A mysterious box discovered in the basement of the National Museum in Prague helped us gain insight into the coexistence of humans and dinosaurs. It contained diaries, a bundle of letters, but also a camera and other necessary things of explorer Věnceslav Brábek from the beginning of the 20th century. It turned out that this brave man traveled through time with help of time centrifuge. He made his first trip to the Upper Cretaceous in the Mesozoic 70 million years ago. In his notes, we can read about scientific research and everyday worries about a roof over his head, food and bare life. Brábek will soon understand that surviving in a time full of predators is not easy. To his surprise, he gets extraordinary helpers, with whom his stay in prehistoric times changes from day to day. He carefully writes down everything, draws, photographs, and also solves the technical problem of how to send letters home to his beloved Aurélia. When a volcano erupts near his home, Brábek returns home, but leaves a piece of his heart in prehistoric time. It is amazing how everything has been preserved, and we can experience many adventures with the dauntless researcher.