Magic Princess Academy 20: The Mystery of Sundae Academy

Under the power of magic, objects in Sundae Academy came to life and spoke!
The awakened moonstone necklace claimed that Princess Milu's mother, Melu, disappeared from Sundae Academy twenty-five years ago, and that it was actually a murder!
To help Milu uncover the truth, Leto and the princesses launched an investigation, only to discover that Teacher Chiffon also had an identical necklace!
It turned out that Melu, Chiffon, and Ivance had used moonstone necklaces as tokens of friendship. After their friendship broke down, Melu disappeared without a trace...
Could Ivance, who suddenly broke off her friendship with Melu, be the mastermind behind the incident?
Could Teacher Chiffon, who was unusually harsh on Milu, also be involved?
What hidden secrets did Milu's complicated identity conceal?
Sundae Academy was about to welcome its twenty-five-year time capsule event. Could the princesses seize this golden opportunity to solve all the mysteries?
"Friends are friends, no matter what changes, they are still friends."