The episode begins with King Kyle Sei being informed about the arrival of Prince Ten'yuu from the kingdom of Zaidera. The king asks Sei to limit her interactions with the prince to protect the secret of her powers. Sei agrees but worries about her ongoing research at the Institute of Medicinal Plants. A plan is devised, which involves Sei staying at the royal palace, commuting to the institute, and taking time off when the prince visits.

Prince Ten'yuu arrives and begins his studies at the royal academy. He is polite, well-educated, and quickly makes friends. Liz, a friend of Sei, gives her a list of plants the prince is interested in and warns Sei to be cautious.

Sei and Prince Ten'yuu unexpectedly meet at the institute. The prince shows great interest in Sei's research on rare medicinal herbs. The royal palace is unaware of the unannounced visit and becomes concerned. Bodyguards are assigned to monitor the prince's movements.

By the end of the episode, Prince Ten'yuu speculates that Sei might be the sought-after "key." Despite his servant's warnings about his status, he decides to take the next step "somewhat rashly," without considering the consequences.