Magic Tree House 4 Books Collection Vol 21-24 By Mary Pope Osborne

Titles In this Set:
Civil War on Sunday 
Revolutionary War on Wednesday
Twister on Tuesday 
Earthquake in the Early Morning

Camelot is in trouble! Jack and Annie must find four different kinds of writing that will help. Their quest leads them to the American Revolution, the American Civil War, the stormy Great Plains, and the great San Francisco earthquake. It's a difficult and dangerous mission, but Jack and Annie will do anything to save Camelot!