Magic Tree House: Books 42 & 43

A Good Night for Ghosts
When the magic tree house whisks Jack and Annie to New Orleans, Louisiana, in 1915, they find out that they have arrived on the eve of All Saints’ Day—the spookiest night of the year! Jack and Annie’s mission is to find a musician named Louis Armstrong and help him bring his gift of music to the world. Unfortunately, he is busy doing anything but playing music! It will take a host of New Orleans ghosts, plus a daring plan from Jack and Annie, to make this mission a success. . . .
 
Leprechaun in Late Winter
The magic tree house whisks Jack and Annie off to a rainy winter day in Ireland long ago! Their mission: to find a girl named Augusta and inspire her to share her creative talents with the world. But when Jack and Annie meet Augusta, they don’t see how they can inspire her at all—she is the least exciting and imaginative person they’ve ever met!
That’s when a magic whistle comes in very handy! But their plan backfires, and soon Jack and Annie are following a leprechaun into the great unknown to rescue Augusta.