Sam, Abby and their friend, Justin, time travel back to 1968 in search of their grandpa's long-lost guitar. They jam with a local garage band, meet a yet-unknown musical group called The J5s, and discover the groovy world of pop stars, mod clothes and teen idols. But when they locate the stolen guitar, the kids find themselves trapped, with no obvious way to return to the present. Their biggest challenge, however, may be to convince their parents that Santa is real, without breaking their promise to keep his identity a secret. This is the third book in the Secret Santa Mystery series.