Himitsu no AiPri: Ring-hen

It's a new semester! Himari and Mitsuki have become second-year students of Paradise Private Academy! Their school lives become more and more lively with the introduction of new underclassmen full of individuality and personality.
In the AiPri-Verse, new AiPri are appearing one after another! Everyone tries their hand at a brand new, never-before-seen Buzzrium Change! In the midst of all this, the mysterious Princess Ring Clover and her butler, Shimitsuu, are holding an Aipri contest. They say the winner will become an admired "Eternal Aipri." Himari and Mitsuki are all ready and full of fighting spirit! But it appears Princess Ring holds a very large secret...
As their friends increase, so does the mysteries of the ring. The Ring arc finally begins!
(Source: Offiical Website, translated)