The Alcatraz Escape by Jennifer Chambliss Bertman

In Unlock the Rock, James, Emily, Nisha and Matthew, Emily's brother, need to find and solve four specific puzzles so they can get a ferry ride to the world famous Alcatraz Island. Many of their fellow students in San Francisco are also trying to win. Before they get to the island, Emily and James get threatening notes in their school lockers. The first step of the competition is fierce.
When they arrive on the island, strange things start happening. First, Fiona, a fellow student, loses her special charm bracelet. Matthew is accused of stealing it. After that, Mr. Griswold almost falls off the tram car going to Alcatraz Island. Then, Emily, known as Surly Wombat in the book search game, bumps into the obnoxious and overconfident 8th grade book searcher who calls himself the Bookacuda. He taunts Emily and her friends by saying that they are going to lose. While all these things are going wrong, Emily is still getting threatening messages on the island. Could this trip get any worse?
Once the puzzle solvers get on the prison island, they find one puzzle after another to try and solve. Emily and her friends have to choose the correct four puzzles to solve in order to get off the island. From talking to actors playing prisoners, to figuring out why the clocks don't match, to addition puzzles, Emily, James, Nisha, and Matthew are in for a tense and thrilling adventure to Unlock the Rock.
Labels: action and adventure stories, Book Scavenger #2, code based plot, fast paced, Jennifer Bertman