Rozen Maiden Vol 2

From the Tokyopop edition

Shinku gets a new servant in Hinaichigo, who, it turns out, belongs to Tomoe, Jun's childhood friend. However, Hinaichigo's insatiable need for companionship might prove harmful to the new doll owner. And when another Rosen Maiden, Suiseiseki, shows up exclaiming that her twin, Soseiseki, has been taken hostage by a bad human, it's time for Shinku and Jun to find the missing doll.

Source: Anime News Network Encyclopedia