Grace, Madison and Albert study at the same university, where they met and became friends. Students enjoyed attending Professor Allan's lectures. He knew how to interest students in his subject, treated his students with respect and they paid him the same. But once in Mysterious Incident, he did not show up for his lecture and did not even warn that it would not be. The guys decided to ask the dean's office about the reasons for his absence, but there, too, they could not answer anything intelligible. And then the trinity decided to go to the professor's house. A surprise awaited them - the door to the house was open, but its owner was not there. It seemed that the professor was going in a hurry and even forgot to lock the door, or maybe he was stolen. The students want to find out and ask you to help them with the Mysterious Incident.