Haru no Noroi

After Natsumi's younger sister and best friend Haru dies at the age of 19, she begins dating Haru's fiancee Togo - on the condition that he take her only to places he had taken her sister. Their relationship deepens as the seasons pass, but Haru's Curse lies between them... Will there be happiness after Haru's Curse is broken?

(Source: Kodansha USA)

Note: chapter count includes two extras.