The romance of shapeshifters and their urban fantasy cousins could easily focus on land animals (as well as birds and mythical creatures of similar habitats). Sea life is much less common. I’ll start using selfies soon, but in the meantime, I can’t pass up the chance to reread a classic: Diane Duane’s Deep Magic.

This is the second book in her Young Wizard series, first published in 1985. In recent years, Duane has updated the series with new editions, but the book remains as in-depth as it has been for nearly four decades. It owes a lot to Madeleine L’Engle’s A Wrinkle in Time and its sequels. Star Wars was still a novelty. Yoda pajamas were a fashion statement for geeks. Personal computers were just beginning to appear in middle-class homes, and mobile phones were still a long way off.

It’s almost a historical novel now, set in Long Island and New York City in the mid-eighties. The Twin Towers are still standing and new. Maps are on paper and research is done at the library with paper books and card catalogs. The kids are free-range – they can go out all day, but they’d better be back by sunset or their parents send out an army.

Young wizards Nita and Kit once saved the universe. Now they have to do it again because that’s what wizards are for. They are supposed to be on vacation-Nita’s parents rented a cottage on Long Island Sound and invited Nita’s friend Kit to join them. Mom and Dad don’t know that Nita and Kit are wizards, although Nita’s bright younger sister, Dailin (in Yoda pajamas), already knows.

When the young wizards spot a wounded whale on the beach, their vacation comes to an abrupt end. Nita can communicate with animals – the whale is much more than that. She’s also a wizard, and the world is once again in great danger and needs Nita and Kit’s help to be saved.

This is a strongly dualistic universe. Wizards exist to prevent entropy. Entropy and death are the work of a solitary force, working through the endless incarnations of itself and its slaves and servants. Every time it’s defeated, it pops up elsewhere, and the wizards have to defeat it again. It never gives up, and almost never surrenders.

This time, the threat comes from the deep ocean off Long Island, well below the surface. Sea shamans are cetaceans of all kinds, from whales to dolphins, who must renew an ancient ritual. If they fail, the sea will erupt, and most of the world will be destroyed.

Servants of the Lone Power have eliminated the High Whale Wizard who was supposed to lead Song of the Twelve. His successor is very young and inexperienced, and she is the whale the human wizard found on the beach.

Nita and Kit were asked to help write the song. In order to do this, they must transform into whales. Nita basically did it through willpower, becoming a humpback. Kit resorts to a more mechanical form of magic: He uses a whale shark, a cloak or shirt made from the neural networks of sperm whales. While Nita can imagine herself in the shape of a whale, Kit must wear an ark to move.

Nita’s transformation can be dangerous if she forgets how to do so, but it’s based on her own mind and will, which she can control with relative ease. By contrast, Kit’s behavior was imposed on him from the outside. The saxophone retains some of the personality of the whale that died to make it. He has to be very careful not to lose himself completely. This is especially true when he is under pressure and when he is involved in a fight. Sperm whales are fighters. They live to fight the monsters of the deep – many of them in the service of solitary forces.

Nita may not be in too much danger with her transformation, but her role in the song more than makes up for it. She agrees to play the role of the Silent Lord but forgets an important piece of advice she received before accepting the assignment: Be sure to read the fine print. By the time she realizes what she’s actually agreed to do, she’s too deep to get out.

These books may appear as upper-middle-grade fantasy adventures featuring teens, but they’re not light, fluffy, “kid-safe” books. They are beautifully written, thoughtful, and unflinching. Deep Magic hit straight to the heart of me, and I haven’t been a teenager in a while.

Of course, there are lots of kid details. Dai Lin is the naughtiest little sister. Mom and Dad are well aware that both she and Kit are on the threshold of puberty, adolescence. Their attempts to enforce deadlines and curfews cause major problems for the young wizards‘ commitment to the ceremony – and the death toll runs into the millions if they don’t attend. Anyway, if theydon’t attend, the world as they know it will be destroyed.

Overall, Deep Magic is a beautifully crafted urban fantasy novel that explores the themes of transformation, sacrifice, and the power of language and music. It is suitable for young adult readers and above, and I highly recommend it to anyone who enjoys a well-written, engaging fantasy story.