There comes a point in every young mammoth's life when it's time to grow up a bit and join the Mammoth Academy. Arabella loves school, but Oscar is finding it a little more difficult to get used to. Especially as he is accused of stealing the school's oranges. He is sure it was humans - the most dangerous animals in all of the Mammoth Lands! With the help of his new friend Fox, who has decided not to wash for 2 months so his fur will begin to self-clean, Oscar sets out to prove that humans are in the valley and at the same time stumbles across more trouble than he'd thought!