Best friends Ellie and Kim are on the hunt for a leprechaun and they know just where to find one. They may not live in Ireland, but they've heard that some leprechauns came to Boston during the Irish Potato Famine in 1845. Kim's grandmother suggests that the best time to find a leprechaun is on a rainy day. Today is the perfect day. The rain is falling and the overgrown orchard behind Ellie's house is the perfect place to start their search.

Sure enough, amongst a fairy circle of unusual mushrooms they discover their first clue-a tiny silver buckle. Leprechauns are known to be sneaky, but the girls are determined to catch the wee folk and secure their fortune in gold.