The Hardy Boys:

What Happened at Midnight

By Franklin W. Dixon

#10

1931

Frank and Joe Hardy receive an unusual assignment from their detective father. They are to "break into" the house of a Bayport neighbor, Malcolm Wright, and retrieve a top secret invention that the scientist had hidden in his study before leaving for California. The invention is in danger of being stolen, and the boys race against time to beat the thieves at thier own game.