The diving lessons begin in earnest, and though still clumsy, Anna pushes forward one step at a time. As she struggles to find her rhythm in the water, Deok-hyun guides her with a quiet, steady presence, seemingly indifferent yet gently attentive. Between them, an unspoken shift begins to surface, and the air around them starts to feel just a little different.

Back in her hometown, the afterglow of Anna's first dive still lingers in the air. As she and Deok-hyun grow closer through shared time in the sea, an unexpected sense of comfort begins to form between them. But just as things start to settle, unsettling rumors about Deok-hyun resurface, quietly disrupting the calm rhythm of their once peaceful days.

Anna uncovers a secret that should never surface, while Deok-hyun is forced to face a past he can no longer turn away from. As they confront their own limits, both are tested on whether they can find the courage to begin again.

Despite a typhoon and a canceled competition, Anna and Deok-hyun continue forward with their friends, refusing to give up. On the ever-changing sea, where nothing can be predicted, each of them is forced to face their own limits and find a way to move forward again in their own way.