I Married This Dragon King Instead of My Sister

Episode 1

Princess Seraphina opens her eyes on the worst day of her life—again. She remembers everything: forcing Cassian, the kingdom's greatest dragonslayer, to marry her with her crown, the war, the kingdom burning, and Cassian dying with a final plea that he never see her face again. He didn't die for her; he died to be rid of her.

So when her father begs her to marry to save the realm, she refuses the man she once obsessed over. "Father, I will not marry lord Cassian. I'll marry the dragon king myself." She has just volunteered for the monster everyone fears.

Episode 2

Her father warns her the words can't be taken back. Seraphina doesn't flinch. In her last life, Isolde was sent to the dragons, broke under it, and took her own life—handing the dragons their reason to burn everything. This time she trades places, letting Isolde have Cassian and going to the dragons willingly. The king orders the decree changed at once.

Then Cassian arrives bleeding from battle, begging the king not to send Isolde to the Dragon King. Seraphina coldly points out the obvious: if Isolde doesn't go, she does. He never once asks what becomes of her. So long as it isn't his Isolde, nothing else counts.

Episode 3

When the decree is read and Cassian learns the bride is Seraphina, not Isolde, he's the happiest man alive. "From this day, you and I are done." She walks away without a backward glance—no clinging, no weeping.

But he doesn't know the truth yet. He storms at her, accusing her of sending her own sister into hell. Seraphina lets him believe it, refusing to explain that the name on the decree is now hers. He swears a decree and an altar will never make her his—that whatever lives in her heart, he'll never touch. She's already decided: this time she won't chase him.

Episode 4

Seraphina strikes Cassian for speaking out of turn, reminding him she's the crown princess and one word could hang him. He apologizes, blaming wine. She tells him the marriage is no longer his concern—it ends exactly as he'd want.

Then his men deliver the mark of healing, a rare treasure that closes even dragonfire wounds. She knows why: her mother raised him, and he's paying her back. That's all it ever was—yet she clung to such gestures for a lifetime. "I don't need it. Send it back." Her servants notice the change. Meanwhile, the decree arrives, and Isolde is summoned to hear her fate.

Episode 5

Isolde assumes Seraphina is scheming—handing her Cassian while stealing her place in the dragon's hell. Seraphina wants only one thing: the day Isolde weds Cassian is the day Seraphina rides for the dragons. Until then, Cassian hears nothing. She swears on her crown that he's Isolde's.

Cassian, believing he's losing Isolde to the dragons, never leaves her side. A memory surfaces: the ocarina her mother taught him to play, the one thing that stopped Seraphina's crying as a child—and his promise to play it for no one but her. Watching him with Isolde now, she tells him she's gone in seven days.

Episode 6

Cassian waits in the courtyard, offering sword lessons as another apology. Seraphina refuses. The truth: she always hated the sound of steel—she only claimed to love the sword because he was proud of it. She no longer has to lie to herself.

He can't understand it. He rode all this way; is this some game to make him chase her? Meanwhile, courtiers whisper that Isolde rides for the dragons while the crown princess carries none of the weight. Seraphina overhears and silences them—then Isolde corners her, demanding what's left of her honor now that Seraphina has taken her place.

Episode 7

A struggle at the water turns ugly—Isolde ends up in the water, and everyone assumes Seraphina pushed her own sister in. Cassian unleashes years of contempt, calling her face a mask for something rotten beneath. He tells her she deserves nothing, that she failed everyone in the kingdom.

Then he kneels and swears a knight's highest oath—on his blade, to protect Seraphina for as long as he draws breath. She answers coldly: her mother put that sword in his hands to keep her safe, and he's pointing it at her. The accusation lands harder than any blade.

Episode 8

Seraphina warns Cassian never to speak of her mother again—the one line he crossed. Later, Isolde needles her in the garden: bound for the dragons, yet still stealing Cassian's heart. When Seraphina reaches for him, he shakes her off without a word. "You're a princess. I'm a knight. Keep your distance."

He offers another apology; she refuses it—not now, not ever again. He tells himself she's only angry, that she could never let him go. But she calmly says that in three days she leaves for the dragon realm, and he'll finally be free to marry the woman he truly loves.

Episode 9

Seraphina's mother's ocarina—her most treasured possession—vanishes, and she finds Isolde holding it. Isolde claims she only wanted to look, but the flute ends up broken in two. Seraphina's fury spills over; she whips her sister for it. Isolde protests she never meant it, that it slipped.

Cassian steps in, offering to mend it with dragon crystal—but Seraphina tells him he has no right. Then, in a flash, the sword meant to protect her cuts her instead. Cassian is stunned: she was always fast enough to dodge before. Why didn't she move? Something strange flickers—like a trick of the mind.

Episode 10

After the wound, Cassian keeps vigil outside Seraphina's door for three days and three nights. She never lets him in—right up to the night before she rides with the dragons.

Through the door, he makes a promise: he'll marry her, spend his whole life making that wound right. He means it. But he still doesn't know the truth—that tomorrow she disappears, and the bride waiting at his altar won't be her at all.

She's already counting down the hours. If you want to see whether the Dragon King's bride ever looks back, start this one tonight.