The Hardy Boys - The Shattered Helmet 52

Enhanced descriptions from Syndetics:

Danger is the name of the game when the Hardys agree to help their pen pal from Greece, Evan Pandropolos, search for a priceless, ancient Greek helmet. Years ago, Evan's uncle had loaned it to Hollywood movie company for use in a silent motion picture, but the treasured helmet had been lost. Picking up foes along the way, the young detectives unearth clues that keep them constantly on the move-from their Greek college campus to California and finally to Greece.

Table of contents provided by Syndetics

• I A Weird Welcome (p. 1)
• II Start Worrying! (p. 13)
• III Firecracker Plan (p. 23)
• IV Trailed by an Amazon (p. 32)
• V Tricky Leon (p. 42)
• VI A Clue on Film (p. 51)
• VII The Mysterious Red Car (p. 58)
• VIII Motorcycle Monsters (p. 66)
• IX The Disappearing Act (p. 79)
• X Flash Flood (p. 88)
• XI Cheese Bait (p. 98)
• XII Suspect Joe (p. 106)
• XIII Los Angeles Rendezvous (p. 113)
• XIV Surprise Phone Call (p. 123)
• XV Cat and Mouse (p. 131)
• XVI Flight to Greece (p. 140)
• XVII Masquerade (p. 146)
• XVIII Sympathetic Vanides (p. 154)
• XIX The Caves of Corfu (p. 166)
• XX Bang-up Roundup (p. 174)