“Besides,” I say, flashing my fangs. “That’s what these babies are for.”

“Now that the seal is broken,” Sthenno explains, “things will change in the abyss. Access to the door from that side will be more orderly. All creatures within will have an equal opportunity.”

“But how many do we let through?” Grace asks. “How long do they get to stay? How far are they allowed to go?”

Ursula shrugs.

“I think that’s up to us,” I say, finally getting the message. “We’re the head girls in charge, and we sail this ship however we see fit.”

“Your sole charge is to ensure the balance in this realm.” Sthenno looks at each of us in turn. “Interpretation of that charge is yours to determine.”

“That is the true responsibility of the legacy,” Euryale finishes. “To balance the freedom of the monster realm with the safety of the human one.” She beams at me. “I am certain you will be fair and generous guardians.”

“But you’ll be here to advise us, right?” Grace asks. “You can help us figure things out.”

My gut clenches. I’m afraid I know the answer to Grace’s question. The gorgons are passing us the torch—preparing us to carry on . . . without them.

My fears are confirmed when Ursula shakes her head.

“We have trespassed in this world too long,” she states. “It is time for us to move on.”

“Move on?” Grace chirps.

“It is time for us to leave this realm,” Ursula says. “To go to Mount Olympus.”

“The Olympians have extended us an invitation we cannot refuse,” Sthenno explains. “In an attempt to make amends for . . . all that has passed, they will elevate us to the rank of goddesses.”

“We shall sit on the council of justice.” Ursula presses her palms to her stomach, and I can tell she’s excited. “We will be able to prevent wars like this from happening in the future.”

“Besides,” Sthenno says, “this world is rightfully yours now. You have earned it.”

I don’t understand why they’re doing it, why they’re leaving just when we’ve made everything right. I want to argue, to tell them we will still need them, maybe more than ever.

But I know how stubborn Ursula is. She’s made up her mind and there is no changing it.

Grace does the arguing for me.

“You can’t leave,” she insists. “We need you.”

Ursula smiles in that way she has that says there is no point in arguing. Goodness knows she’s given me that look enough over the years.

“You have all that you need right here.” She gestures at me and my sisters. “As long as you have each other, you will not fail.”

“And as this afternoon has proved,” Sthenno adds, “you have abundant help should you need more.”

My emotions break free. I rush forward and hug Ursula.

“Thank you,” I whisper so only she can hear. “For . . . saving me.”

“It is you who saved me.” She leans back, presses her palms against my cheek. “You are the daughter I could never have.”

My chest tightens, because that’s how I feel too. She is the only mother I’ve ever known. The thought of losing her . . . it hurts. But if she’s taught me anything, it’s how to push past the pain.

When she pulls away, taking her sister by the hand, I let her go.

“With our departure,” she says, “we give you not only the legacy of guardianship. . . .”

“We give you our immortality,” Sthenno finishes.

“Immortality?” Grace echoes.

Greer stands utterly still.

“There is a catch,” Sthenno says. “We have but two immortalities to give.”

“The balance must remain as before,” Euryale explains. “Two immortal sisters . . .”

“One mortal,” I fill in.

She nods. “We shall leave it to you three to decide. When you are ready, speak the decision and it will be done.”

Grace, Greer, and I exchange a glance. Grace looks confused. Greer looks terrified. I’m sure I look determined. My sisters can have the immortality. I refuse to watch either of them die.

“Time to go, sister,” Sthenno says, tugging at Euryale’s hand. “Olympus awaits.”

“Good-bye, Gretchen, Grace, and Greer,” Euryale says. “The world is safe in your hands.”

Then, as I watch, they disappear into mist. I can’t stop the tears from streaming. Except in those moments before we brought Greer back to life, I have never felt so much emotional pain. I have to physically squeeze myself to keep from sobbing.

Next thing I know, I’m wrapped in a big hug with one sister on either side.

“I love you both,” Grace says. “So much.”

I suck in a deep breath. “Me too.”

There is such a long pause that Grace and I pull back. Greer is scowling as tears stream down her cheeks. She looks like she’s struggling to keep it all together.

“Oh, all right,” she finally blurts. “I love you too.”

I smile at my sisters. I’m amazed by how far we’ve come—how much we’ve grown and changed and accomplished—in such a short time. We are amazing, and the monster world had better behave, because the Key Generation can kick some serious beastie butt.

We found and opened the door between the realms without even a single casualty on our side. We’re taking up the legacy that began with our ancient ancestor, Medusa, and has been passed down through countless generations. We have each other, we have boys and friends and family who care about us, and we have definitely earned the right to enjoy the moment.