The princess is Katerina, of the kingdom of Taina, and now the island has two bridges: one that only Ivan can see, leading back to the 20th century, and one that only Katerina can see, which leads to her time, though if they hold hands they can see the other bridges. Katerina leads him back to Taina, which, to Ivan's surprise, is a Christian kingdom, centuries before anyone thought there would be. Taina is under the grip of Russian arch-villainess Baba Yaga; she claims to be its rightful ruler, and will hold onto her claim until Katerina is married.
Though Katerina and Ivan do indeed get married, they become aware of a plot led by the kingdom's strongest druzhinnik (knight) Dimitri to kill Ivan once an heir is conceived. Instead of consummating, Ivan and Katerina escape to the enchanted grove where they met, and together return to Ivan's time. Now it is Katerina's turn to be dazzled and hindered by a new world. Even worse, their escape does not derail Baba Yaga, who, exerting much of her power, follows them to the 20th century, where she lacks Bear's power but none of her cunning. Returning to Cousin Marek, Ivan discovers that he is, in fact, the god Mikola Mozhaiski, immortal but far reduced in power now that no one believes in him (one-eyed Bear is the same, though he "came out to give a hard blow to Napoleon, and again to stop Hitler"). He thinks his problems are solved, but Baba Yaga's presence, and Mikola's lack of ability in martial areas, results in the newlyweds embarking on a honeymoon... To America, where hopefully Baba Yaga cannot follow.
Ivan's mother Esther receives Katerina warmly, and Ivan discovers to his consternation that she too uses magic; she is heir to the same mystical and ethnic traditions as Katerina. His father Piotr is less sanguine, while Ivan's betrothed Ruth is incensed. In the meanwhile, Katerina learns new spells from Esther; Ivan and Piotr grill Katerina on the details of her times and language; and Ivan uses the Internet to find the details on producing gunpowder, vodka for Molotov cocktails, and a hang glider, potent weapons for use against Baba Yaga and her army, which is driven primarily by fear.
That night Katerina uses a magic spell to check on her father, and discovers that Dimitri has led a coup and poisoned King Matfei with a potion from Baba Yaga, which has rendered him mute. Meanwhile, Ruth, bent on revenge, buys "love potions" from a gypsy crone and then proposes a day-early Fourth of July picnic with the happy couple. Unbeknownst to her, however, the crone is actually Baba Yaga in disguise, having negotiated airports, airlines and customs using magic and observation, and only some quick wits and Esther's enchantments keep the "love potions" from killing Ivan. All in all, it is clear that Katerina and Ivan must return to Taina. That night at dinner, Ivan pledges her his support, but gets only a sorrowful smile for his troubles. Rejected, he retires to his bedroom, and is surprised when Katerina joins him, having slept in separate bedrooms until then. He wonders at her motive. A political statement? A declaration of war on Baba Yaga? No, she tells him; love.
Esther bedecks Ivan and Katerina with charms and wards for the journey across, during which they will undoubtedly be hounded by Baba Yaga. Ivan takes extra precautions by booking their flight to JFK airport out of Greater Rochester International Airport instead of the more convenient Syracuse Hancock International Airport, because Baba Yaga may not know about it. She figures it out, though: a prickling of suspicion, aided by one of Esther's charms, makes Ivan forgo their scheduled plane flight, and he and Katerina pack up and leave. Shortly after takeoff, the plane disappears from radar. Baba Yaga leaves the 20th century at the same time. With more time on their hands, Ivan and Katerina take the time to scout out natural deposits in the area of Taina (Cousin Marek's house is right where King Matfei's palace had been) and build a makeshift hang glider before taking the bridge home.
Though Dimitri has declared martial law for Taina's protection, he is not a deft ruler, and the people rejoin Katerina and Matfei with open arms. They then plan their campaign against Baba Yaga. She has been using her captured Boeing 747 as a sort of chariot—the contemporaries describe it as a house with chicken legs—and is holding its crew and passengers prisoner in her castle. On the field of battle, Ivan will lead a group of grenadiers to winnow away her army, while Matfei and his men stand and fight. Katerina, meanwhile, will use a hang glider to enter Baba Yaga's castle and free the prisoners. The battle goes mostly to plan, although Dimitri betrays the king at a crucial time, before being slain by Sergei, a monk friend of Ivan. At then end of the battle, Baba Yaga, using Ivan's real name in a spell, traps him in the 747 and then switches place with Bear.
Ivan faces Bear, who has already let slip some significant information to Katerina: namely that he and she will trade places exactly when Baba Yaga's spell goes off. Katerina uses that opportunity to lay a trap, which holds Baba Yaga for several minutes. Bear says he's going to kill Ivan, not out of spite but simply because "it isn't right for someone to put out the eye of a god and walk away." Ivan, however, realizes that he is right near his intended seat, where Katerina accidentally left a book bag containing a potent spell that breaks Bear free of his enslavement. In Baba Yaga's castle, the prisoners escape, and are eventually discovered in a forest in modern-day Ukraine. Katerina also makes her escape just before the place collapses in the absence of Bear's magic. Baba Yaga, though alive, is never seen again.
The final chapter takes place ten years later. Ivan is a celebrated scholar for his contributions to the field of Russian linguistics, and every year he and Katerina, along with their four children, return to Taina for the summer using the magic bridges. None of the children can cross without their assistance, and they face the ever-looming question of who will end up living when. Regardless, Ivan and his Sleeping Beauty have finally found their happy ending.