The "bittersweet, mysterious story" revolves around Chocolat Aikawa, a chocolatière who runs a shop called Chocolat Noir. She can grant wishes to the troubled people who visit her shop -- if they give her something precious in exchange.

In the Chocolat no Mahou (The Magic of Chocolate) series:

V.01 - Chocolat no Mahou
V.02 - Bittersweet
V.03 - Creamy Sugar
V.04 - Dark Spice
V.05 - Evil Essence
V.06 - Fruity Flavor
V.07 - Guilty Crunch
V.08 - Honey Blood
V.09 - Ice Shadow
V.10 - Jewel Syrup
V.11 - Knocking Egg
V.12 - Love Flake
V.13 - Melty Night
V.14 - Nutty Carnival