Magic Tree House: Books 11 & 12
This collection includes:
Lions at Lunchtime
Jack and Annie are whisked off to the vast plains of Africa, where they must solve Morgan le Fay's third magical riddle. But that's only the beginning! Once the riddle is solved, they still have to get past a pride of lions, a humongous herd of rampaging wildebeests, and one very hungry Masai warrior.
Polar Bears Past Bedtime
The Magic Tree House transportss Jack and Annie to the freezing Arctic. There, they must solve the final riddle to become master librarians. But it's not going to be easy--especially when they have cracking ice, a seal hunter, and a prodigious polar bear to deal with. Will they be able to solve the riddle before they get iced themselves?