The Thirteen Treasures of Britain - Merlin's Last Magic, #1

1, 400 years is a long time to be asleep. Even for a wizard. Especially for a wizard who has to stop an ancient prophesy from coming true. By the time Merlin wakes up from his enchanted sleep, it's 1985, the legendary Thirteen Treasures of Britain are missing, and his magic is starting to fade. To make matters worse, in twelve days' time, it will be Midsummer: the prophesied day when the old gods will return to Britain and wreak havoc on its people.
If the Treasures fall into the wrong hands, the gods will rise, thousands will die, and Britain will be utterly transformed by chaos. In the old days, the days of Camelot and King Arthur, Merlin would've sent someone else on the quest for the Treasures. But now, with time running out and everything at stake, he's ready to take up the quest himself. The search for the Treasures will take him from the realms of Faerie to the Land of Dreams, and from the streets of Glastonbury to the distant reaches of the solar system, where he'll meet friends and foes alike, including Arthur Pendragon, Morgana Le Fay, and a panther-like creature called the Cath Palug: the "slashing cat" with a taste for king's blood.