Ever since they discovered the door under the stairs, Emil, Joe and Hanna have had many adventures travelling to the past. In the Case of the House at No. 74, they went back in time and met the heroic nurse, Sybil Kathigasu.

This was a very dangerous time in history and the three friends narrowly escaped as they tried to help Sybil. They also discovered they were not the only ones who have been going through the door back to the past!