When eight-year-old Jack and his seven-year-old sister, Annie, join a group of nineteenth-century explorers aboard the H.M.S. Challenger, they learn about the ocean, solve the mystery of its fabled sea monster, and gain compassion for their fellow creatures.
Magic tree house Merlin missions ; #11
Challenger (Ship : 1872-1876) -- Fiction.
Compassion -- Fiction.
Magic -- Fiction.
Oceanography -- Fiction.
Time travel -- Fiction.
Tree houses -- Fiction.