They'd Always Trusted Him--Until Now....A morning flight over Helsingor turns dangerous when the pilot, Matthias Karlsson, blacks out without warning. Almost as terrifying is the find thirteen-year-old Peter Andersen makes in the cockpit--a hidden handgun! When Matthias comes to just in time to save their plane from crashing into the sea, Peter puts the shocking discovery behind him--for the moment.Certain Matthias is hiding something, Peter persuades Henrik Melcoir to join him in spying on the man, and the friends witness a suspicious nighttime meeting with a foreign ship captain. What's worse, a mysterious stranger appears to be spying on Matthias, too.Suddenly, Peter, Elise, and Henrik find themselves at the center of a dangerous plot. If Matthias is involved, are the Melchoirs in danger also? If so, Peter may be about to lose his best friend!