Hisashi and Mai are set to have their wedding ceremony in 3 months, but Mai falls ill and lapses into a coma. Hisashi does not give up on his fiance and prays for her recovery. Finally, Mai wakes up, but she doesn't have any memory of Hisashi.
(Source: AsianWiki; edited by MyDramaList)
~~ Adapted from the book "The 8-Year Engagement: If You Woke Up" (8年越しの花嫁 キミの目が覚めたなら) by Nakahara Hisashi and Mai (中原尚志・麻衣).