The Prisoners and the Paintings — David A. Poulsen

Salt Bellamy and Pepper McKenzie (with Salt's little brother Hal in tow) have braved vampires, robots, and cave-dwellers -- and in Book 5 of this lively series, the two friends make their most incredible discovery yet: Hal is a talented artist! When his painting is chosen by a gallery in Florence, Italy, Salt and Pepper head to Europe together. What they find in this remarkable painting, however, is a bit unexpected -- and leads to adventure!