All six Bastable children—Dora, Oswald, Dicky, Alice, Noel and Horace Octavius—are ambitious adventurers, digging detectives and intrepid treasure seekers by nature. Unfortunately, the Bastable family is currently facing an uncertain financial future.

When father takes ill, and his business partners abandon him, the six children team up in an effort to restore their family’s wealth. Although they devise some ingenious escapades, their efforts usually end up unprofitable but fun—and sometimes their digging gets downright dangerous. But one day their adventure leads them to completely unexpected results.