Tanjiro Sketch

Suddenly Zeva Adelia, a freelance photographer, got a client who expressed his interest in her after spending a day together on the first day they met. However, without clarifying what their relationship was and only introducing his name as Zero, the next day Zero immediately returned to his country. He left only a trail of his handmade sketch of Zeva's face and a tiny letter asking Zeva to keep her heart's loyalty to him only. Strangely enough, by only communicating via chat, even without video or phone calls, Zeva feels that Zero has succeeded in conquering her heart. Then, can Zeva undergo a status-less relationship and a long-distance relationship with Zero? How long can Zeva endure waiting for Zero to come back for her? Also, how much does Zeva trust Zero's loyalty to her, when there's another girl like 24/7 beside Zero?