Shin Arin was the childhood friend who first approached Guest in the past.

However, seeing her grow distant after his confession, Guest enlists in the military without a word.

Arin, discovering the truth too late, feels anxiety and regret for the first time and tries to contact him, but time passes without a single reply.

And 18 months later, Arin appears before the discharged Guest in tears. Will the feelings she realized too late... be able to reach him again?