Winter of the Ice Wizard

In this installment of the Magic Tree House series, the magician Merlin sends siblings Jack (age ten) and Annie (age nine) on an adventure to a mythical frozen land using a magical tree house that transports them through time and space.

Jack and Annie are making Christmas cookies with their mom when she mentions it is the winter solstice. Recalling that Merlin called for their help on the previous summer solstice, they race to the Frog Creek woods and find two friends climbing into the tree house: Teddy, a young sorcerer apprenticed to the enchantress Morgan le Fay in the legendary kingdom of Camelot, and Kathleen, a selkie girl, one of the ancient seal people.

Teddy explains that Merlin and Morgan have vanished from Camelot. He and Kathleen found a message in Merlin's chambers, written on a small gray stone, instructing Jack and Annie to travel to the Land-Behind-the-Clouds, head toward the setting sun, and retrieve Merlin's stolen Staff of Strength, a powerful magical artifact, or all will be lost. Teddy and Kathleen insist on coming along, and Annie wishes them all to the Land-Behind-the-Clouds. The tree house transports them.

They arrive atop a snowdrift on a vast, treeless plain. Kathleen, whose selkie nature sharpens her senses, spots wolves in the distance. As the light fades, they discover a glimmering palace made of ice blocks. Inside, a booming voice welcomes them. On a throne sits a huge, bearded man with a black eye patch: the Ice Wizard, also known as the Wizard of Winter. He scoffs that they are mere children, but Annie convinces him by describing the message. The wizard reveals that he, not Merlin, wrote it. Jack realizes they have been tricked.

The wizard dismisses Teddy and Kathleen because they are not mortals. He rips off his eye patch to reveal an empty socket and demands that Jack and Annie retrieve his missing eye, which he traded long ago to the Norns, supernatural sisters who govern destiny, in exchange for wisdom that never came. Only mortals can undo the bargain. He gives Jack a wind-string, a knotted cord that summons wind when untied, and directs them to take his sleigh to the Norns' home, pay whatever they demand, and return his eye by dawn. He warns that white wolves will devour them if caught. Picking up a carved stick that Teddy recognizes as Merlin's Staff of Strength, he threatens they will never see Merlin or Morgan unless they succeed, and blasts all four outside.

A strange silver sleigh shaped like a small sailing ship glides out from behind a snowbank. A wolf howl pierces the silence. They scramble in, and Jack unties knots in the wind-string until the sleigh shoots forward, leaving two white wolves behind. Teddy steers while Kathleen guides them toward the sea.

They reach sea ice and find the Norns' home, a snowy mound with a chimney. Inside, three skeletal sisters weave at a loom. The Norns greet them warmly and recount the wizard's story: He traded one eye for wisdom, but the seeds of wisdom they planted in his heart never grew. They gave his eye to the Frost Giant, a blind, destructive force of nature, hoping sight would teach it to appreciate beauty, but the giant never used the gift. The eye now lies inside the Hollow Hill, a hill with no peak: In a hole within the hill is a hailstone, and inside the hailstone hides the eye. The gray Norn warns that looking directly at the Frost Giant means instant death. As payment, the Norns ask for Annie's red scarf, which she gladly gives.

The gray Norn shares another detail: The wizard had a younger sister who loved him deeply, but after a foolish argument he told her to leave forever. Heartbroken, she joined swan maidens, donned a feathered dress, and flew away. The wizard grew cold and cruel. The Norns say their own powers are fading and that Jack and Annie will shape what comes next.

Only mortals can undo the bargain, so Teddy and Kathleen promise to meet Jack and Annie at the palace by dawn. Jack and Annie sail north, find the Hollow Hill, climb through a crack in its slope, and descend into a deep hollow. Annie discovers a small hole in the floor and pulls out a chunk of ice the size of an egg: the hailstone.

The ground trembles and a loud huffing grows closer. Jack and Annie hide, covering their faces to avoid looking at the giant. Its breath howls through the hollow. When it seems to fall asleep, they creep toward the exit, but the giant wakes with a roar and blasts them with wind. They scramble outside, and an avalanche buries Jack. Too exhausted to free himself, he loses consciousness.

Jack wakes to find white wolves crouching near him and pawing at Annie. Fueled by protective anger, he shouts and hurls snow until they retreat. Annie confirms the hailstone is safe, and they race to the sleigh as dawn approaches.

They reach the palace at sunrise. The two white wolves sleep beside the wizard's throne. The wizard cracks open the hailstone and fits the eye, a white marble with a sparkling blue center, into his socket. But the eye does not move. He flies into a rage and grabs the Staff to attack them.

Teddy bursts in, and Kathleen enters with a young woman in a white feathered cloak: the wizard's long-lost sister. She smiles at him, and an ice-blue tear leaks from his frozen eye. The eye begins to work. She tells the wizard she has come to forgive him. Teddy explains that a seal led him and Kathleen under the ice to the Isle of the Swans, where Kathleen persuaded the sister to return.

Annie demands the wizard keep his promise. He hands her the Staff and tells her to call for Merlin and Morgan. She and Jack grip it together, and Annie calls out. A burst of blue light transforms the two white wolves into Merlin and Morgan le Fay. Morgan explains the wizard turned them into wolves, and they were following Jack and Annie to protect them. The wizard admits he lied about the wolves being dangerous because he feared the children would discover their true identity.

Morgan tells the wizard he can see not because his eye was returned but because his heart was: His sister's forgiveness restored what was truly missing. Merlin adds that wisdom comes from the heart as well as the head. The wizard asks forgiveness, and Merlin invites him to visit Camelot as a guest. Merlin also reveals that there is no actual Frost Giant; the howling in the Hollow Hill is caused by cyclone-like storms. He praises Jack and Annie and says their next adventure will take place in their own world.

Jack and Annie return to the tree house and wish themselves home. No time has passed. Walking home, they find Annie's red scarf on the porch railing, returned by the Norns, with a tiny woven picture of Jack, Annie, and two white wolves. Their mom calls them inside, where the Christmas cookies are ready.