From MangaHelpers:
A childhood friend is someone you held a special bond with many years ago, during your younger days. When you become an adult, this special bond can be held dearly, taking it from the level of friends to mature love. Now, follow couples who are childhood friends and see how their special bond has been carried into their present life. Did a lady, confessed to by a man, years later, give the response he desired? Was the man, who was present at the death of the girl’s mother, later the only one able to sympathize with her? Did the two once make a promise to go somewhere, only to do it in the present? Find out yourself how these childhood friends became lovers.