Samantha is excited about her family's stay at a fancy new "apartment-hotel" - until she learns there's a terrible curse on the building's owner! As soon as Samantha arrives, one thing after another goes alarmingly wrong. Is it the curse - or is something else scaring the residents from Ravenscourt?

Samantha and Nellie set sail for Europe in 1906. Also aboard the ship is a world-famous archaeologist and the legendary sapphire he is carrying to a London museum. When his priceless jewel disappears, Samantha realizes that every one of the first-class passengers is a suspect—and one of them must be the thief!

Samantha can't wait to take Nellie to Piney Point, Grandmary's summer home in the mountains. Samantha is sure that Nellie will love the lodge as much as she does. But the girls arrive to find Piney Point plagued with accidents—and Grandmary thinking of selling. Samantha and Nellie have to figure out what's going on before they lose Piney Point forever!

When Samantha and Nellie travel to England with Grandmary and the Admiral, they visit an old friend of the Admiral's—an English knight who lives in an ancient manor house, next to castle ruins that are rumored to be haunted. They glimpse strange sights in the castle tower at night—and learn that valuable old books are disappearing from the manor's library. Samantha and Nellie join forces with the knight's mischievous twin nephews to find out who—or what—is behind the strange goings-on.

Samantha and Nellie are thrilled to visit Paris with Grandmary and the Admiral! But what could be behind the Admiral's secret government meetings? After a suspicious accident and a break-in at their hotel suite, the girls are worried. Is someone trying to harm their beloved grandfather and stop his secret mission? Includes a glossary of French words and an "Inside Samantha's World" essay about tourism and international tensions in Europe in the early 1900s.