The anime is set in Holy Girls Square Academy, an academy for training pro star performers. The anime will focus on students who aim to participate in the academy's annual big event, the Girls' Arena. (Source: ANN)

Corrupt politicians, frenzied nationalists, and other warmongering forces constantly jeopardize the thin veneer of peace between neighboring countries Ostania and Westalis. In spite of their plots, renowned spy and master of disguise "Twilight" fulfills dangerous missions one after another in the hope that no child will have to experience the horrors of war. In the bustling Ostanian city of Berlint, Twilight dons the alias of "Loid Forger," an esteemed psychiatrist. However, his true intention is to gather intelligence on prominent politician Donovan Desmond, who only appears rarely in public at his sons' school: the prestigious Eden Academy. Enlisting the help of unmarried city hall clerk Yor Briar to act as his wife and adopting the curious six-year-old orphan Anya as his daughter, Loid enacts his master plan. He will enroll Anya in Eden Academy, where Loid hopes she will excel and give him the opportunity to meet Donovan without arousing suspicion. Unfortunately for Loid, even a man of his talents has trouble playing the figure of a loving father and husband. And just like Loid is hiding his true identity, Yor—who is an underground assassin known as "Thorn Princess"—and Anya—an esper who can read people's minds—have no plans to disclose their own secrets either. Although this picture-perfect family is founded on deception, the Forgers gradually come to understand that the love they share for one another trumps all else.

With Anya Forger successfully enrolled at the renowned Eden Academy, Operation Strix advances to its second phase. To investigate Ostanian politician Donovan Desmond, Anya must either befriend his son Damian or collect eight Stella Stars to become an Imperial Scholar. Fortunately, Anya has already acquired her first star. In celebration, her adoptive father, Loid, decides to fulfill her wish to adopt a dog. During their canine search, Loid receives new orders from his superiors, who have found that a band of Berlint University students is plotting to assassinate Westalis' Minister Brantz using bombs worn by trained dogs. While Loid tries to stop their plans, Anya stumbles upon the terrorists' base of operations. There, she befriends a kindhearted, clairvoyant dog who the family later names Bond. Although the Forgers continue to lead their individual lives in secrecy, the family—with a new fluffy addition—remains united through all of the unusual obstacles thrown their way.

With her ability to read minds, Anya Forger is the only one who knows the true identities of her unconventional family. Her pretend father Loid operates as an elite spy code-named Twilight; her mother Yor kills on demand as the assassin Thorn Princess; and their dog, Bond, possesses the gift of precognition. Although they hide the truth from each other, this pretense of a perfectly ordinary family provides Anya with the genuine love and warmth that she longed for as an orphan. Operation Strix—Loid's special mission to avoid potential war by gathering vital information and getting close to the powerful political figure, Donovan Desmond—is only possible if Anya plays her part right. She can either excel academically and become an Imperial Scholar at her prestigious school or make friends with Donovan's son, Damian. Neither is exactly easy, but with her adventurous attitude, Anya throws herself wholeheartedly into her mission as a Forger—all for the sake of international peace.