When love survives everything, only one promise remains: eternity.
After division, loss, and sacrifice, Ally thought she had reached the end of what she could endure. But when old enemies rise one final time, she realizes the most important truth is not behind her.
It is still waiting ahead.
Now fully herself, guided by the return of memory, Ally must face the final battle beside Yale, the man who never stopped watching over her.
Between Olympos, Earth, and forces willing to destroy everything, love, loyalty, and destiny will be tested as never before.
Because some souls find each other across lifetimes.
Some promises survive death.
And when everything seems lost, one thing still remains powerful enough to change the universe:
eternity.