When Henry finds a strange baby hidden among the flowers in Aunt Agatha's garden, it looks like another adventure is in store - especially when little Sweetheart sprouts antennae! But when a host of ghostly women begin to haunt 131 Ballantyre Road, all desperate to catch a glimpse of the baby, Henry and his new friend Rosie know this is a job for the magical, marvellous Harvey Angell.

Henry's extraordinary friend quickly realizes that Sweetheart isn't from this world - she's from the future, and she needs to get back home before it's too late. That means a breathtakingly dangerous trip through time for Harvey Angell . . .