Molly is back from Amer-i-kay! On her return she tracks down Bram to his new family home in Buckingham Street, Dublin. On a visit with Bram's family to the relatively newly-built Natural History Museum of Dublin (the Dead Zoo) Bram and Molly meet and befriend a quiet, shy young boy from India called Sanjit. Sanjit's uncle, cranky Professor Seth Kumar, is working at the Museum. Sanjit, has never met his uncle, but has been sent from India to stay with him for a time.

Bram enlists his old friends Molly, Her Majesty the dog and the Sackville Street Spooks, to help show Sanjit the sights of Dublin. They have several adventures in the city - including visiting Waxie's Dargle - the famous annual picnic in Irishtown.

When the Natural History Museum is burgled and vandalised and Sanjit's uncle suddenly vanishes Bram and Molly vow to help Sanjit find the Professor.

Can Bram and Molly, with the help of the Sackville Street Spooks, find out where the Professor has gone? Can they follow the clues in an ancient treasure map and defeat the curse of the Dead Zoo?