Magic Tree House
Books 7 & 8: Sunset of the Sabertooth, Midnight on the Moon
The magic tree house transports Jack and his sister Annie on a mission to the Ice Age where they encounter Cro-Magnons, cave bears, sabertooth tigers, and woolly mammoths. It also takes them to a moon base in the future where they continue to search for the fourth thing they need to free their friend Morgan from the magician's spell.
