It is the summer before senior year and friends Carly and Ashley have the perfect plan. There is a student trip planned for London, England that Ashley is supposed to be on while her parents head off to Hong Kong for a week. But that will ruin her plans to ride her horse in the upcoming equestrian trials. The friends have it figured out though. Carly will pretend to be Ashley and go on the student exchange to London so Ashley can stay at home and ride her horse Brock in the trials. What could go wrong? Carly will get a break from her sad family situation and be able to get over her broken heart and Ashley will have a quiet peaceful week at the stables. Carly (in the guise of Ashley) joins Lindsay, Kristen, Sienna and Sonnet on the trip of a lifetime.

All of the girls are looking forward to new experiences, new worlds (and great shopping). But the trip will change them as well. Will the strong friendships they had before the trip survive? And will new friendships and experiences change the girls lives forever?