The album concept is a tale of love, loss, and separation told through the story of two fictional seventeenth-century lovers. A Dutch sailor embarks on a two-year voyage, leaving his wife at home in Holland. The only way for the couple to communicate and keep their love alive during the long separation is through letters. These letters form the basis for the songs on the album.
The Diary double album - close to a year in the making - is an epic production of Ayreon proportions featuring two contrasting interpretations of the same songs, all composed specifically for The Gentle Storm: acoustic / folk arrangements (CD1 - Gentle) and a full-on metal assault (CD2 - Storm). It also heralds Anneke's return to the realms of heavy guitars and soaring vocals reminiscent of The Gathering's breakthrough album, Mandylion. Of course, it wouldn't be an Arjen Lucassen project without his trademark progressive elements, but he readily admits his main focus was on Anneke's vocals.