Neal and Peter are called in to help settle a dispute between two brothers arguing over the fortune of their very eccentric, astronomy-obsessed father. It seems the old man left his sons competing wills, but closer examination reveals that the two documents actually create the first in a series of clues that will lead to the real will. An inveterate puzzler, Peter is thrilled at the possibility of participating in a real life treasure hunt, but the brothers want nothing to do with what is simply another one of their father's crazy games. Peter is disappointed, until Neal points out that it couldn't possibly hurt if the two of them investigated the clues on their own.
At the same time, Mozzie and Neal continue to plan for their great escape. In order to add a little coin to their getaway coffers, Mozzie has lined up a buyer for one of the paintings. But when Neal learns that Peter has secretly called in an agent from the art crimes bureau in D.C., he worries that their movements may not be as under the radar as he had hoped.
Meanwhile, Neal, Mozzie and Peter giddily embark on the treasure hunt. However, when the six-year-old daughter of one of the brothers is kidnapped and held for ransom, finding the will goes from a quirky bit of fun to a matter of life and death.