Wolfcub: Nidhogg (Wolfcub #7)

"Wolfcub, Tjahzi, and Yasmina have reached the In-Between World where Nidhogg, guardian of Yggdrasil, was banished. Thorgal's daughter wants to convince the great serpent to resume his duties and protect the sacred tree from the Dark Elves' onslaught. But Nidhogg may not be the most reliable of allies... The future of Asgard - and that of the human world - rests on a little girl, her mother, and perhaps a bird-brained god!"