"It's the third day of summer vacation, and Lark's halmoni--that's Korean for grandmother--has promised to take Lark and her twin brother, Connor, to the library. The only trouble is, they arrive to discover that Mrs. Robinson, the town librarian, has lost her key. Can rookie detectives Lark and Connor solve the mystery of the missing key?"--Back cover.

"In this illustrated early chapter book, super sleuths Lark and Connor Ba must investigate a threatening note and stolen watch while they are helping set up for the Run in the Sun fundraiser."--