Summer of the Sea Serpent (Magic Tree House Merlin Mission)The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy to use numbering system! Jack and Annie are off on another mythical mission at the request of Merlin the magician. Luckily, they have a young sorcerer, Teddy, to help them. From underwater caves to a Spider Queen, from mystical selkies to a magical sword, this is a Magic Tree House adventure kids wont want to miss! Formerly numbered as Magic Tree