Luna, Konstantin and Aidan are time-travelling thieves working for The Butterfly Club. When they are asked to steal a little-known painting called the Mona Lisa, Aidan can only think of one man who can make things disappear – the magician, Harry Houdini. And as luck would have it, Houdini cannot resist a challenge. The three children and Houdini travel to 1911 Paris where they face an impossible task – stealing a painting right off the wall of the fortress-like Louvre Museum. As Houdini prepares for the theft, a heist which will require him to pull off his greatest ever trick, the time-thieves realise that the Mona Lisa is smiling because she holds a secret. Her creator, Leonardo Da Vinci, hid mysterious codes within the painting. The race is on to solve the puzzle in time...