Ember Lynn, owner of Joycom Inn, and Pyrobin Hunter, an artist, appear to be a loving couple. Yet, their true identities are rival assassins, Scarlet Flame and Cold Blade. Hiding their roles to protect each other, they plan to leave the martial world but must first retrieve the mysterious Paon Box for their organizations. As they clash and probe one another, they uncover a deeper conspiracy pulling them into a dangerous vortex.