The Three Investigators and the Sinister Dragon

Was Mr. Allen reporting a joke when he spoke of a sea monster he claimed to have seen? Whose creepy voice is that on the phone, for example? And what kind of person is Mr. Shelby? He calls himself a specialist in tricks and pranks of all kinds – but he's taking it way too far... Our three friends, Jupiter, Bob, and Pete, once again have to deal with many strange occurrences.

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