Lug the woolly mammoth, Martie the passenger pigeon, Quito the Collins' poison frog, and Scratch the saber-toothed tiger--all from animal species thought to be extinct--are expert members of the secret organization ROAR--Rescue Ops Acquisition Rangers. With great skill, spy tech, and lots of humor, this new team takes on its first mission--heading to Siberia to stop a rival enemy from retrieving a newly thawed, ancient unicorn horn.