The Last Musketeer — Stuart Gibbs

On the first day of a family trip to Paris, Greg Rich's parents disappear. They're not just missing from the city -- they're missing from the century. So Greg does what any other fourteen-year-old would do: He travels through time to rescue them.

Greg soon finds out that his family history is tied to the legendary Three Musketeers. But when he meets them, they're kids his age, and they'll only live long enough to become true heroes if he can save them. To rescue his parents, Greg must assume the identity of a young Musketeer in training and unite Athos, Porthos, Aramis, and D'Artagnan -- but a powerful enemy is doing everything possible to stop him from succeeding.