Magic Tree House: Afternoon on the Amazon

Yoto says: There's a rumble in the jungle, a journey to be made! The sixth story in The Magic Treehouse Series.
Vampire bats and killer ants? That's what Jack and Annie are about to run into when the Magic Tree House whisks them back in time to a South American rain forest in search of the elusive Morgan le Fay. It's not long before they get hopelessly lost on the Amazon River. Will they be able to find their way back to the tree house before they are trampled by stampeding killer ants?