Ep 21. The Secret Garden

Rin Okumura and his friends are continuing their efforts to better understand their own abilities while at the same time protecting humanity from the increasingly dangerous threats coming from Gehenna. In episode 21 of Blue Exorcist, titled "The Secret Garden," the group discovers a mysterious and long-forgotten garden hidden behind a locked gate on the school grounds.

As they explore this hidden sanctuary, they find that it is teeming with both beauty and danger. Plants and animals alike have been imbued with demonic power, rendering them both alluring and deadly. The group's curiosity is piqued by the garden's strange aura and they begin to investigate its origins.

Their research leads them to the discovery of a long-ago incident where a powerful demon had infiltrated the garden and had been able to breed its demonic offspring amongst the plant life. This discovery leads them to realise that the garden itself serves as a nexus point between the human and demon worlds, a point that had been quietly watched by the True Cross Order for many years.

However, it soon becomes clear that some within the Order are not content to leave the garden to its natural affairs. Rin finds himself increasingly at odds with his superiors, as he believes that the garden should be left alone to thrive in its own way. But others in the Order see the garden as a useful tool, one that can be exploited to help them better understand the workings of Gehenna and its demons.

As the conflict within the Order comes to a head, Rin and his friends must make a decision about whether to stand with their superiors or to take a stand against them. The situation comes to a head when one of the group's own is possessed by one of the demonic plants within the garden. The group must work quickly to save their friend and prevent the garden from becoming a dangerous force in the world of humans and demons.

As with every episode in Blue Exorcist, "The Secret Garden" is a dynamic and fast-paced look at the world of exorcism and demonology. The episode is a perfect showcase for the intricate, detailed animation style that Blue Exorcist is known for, as well as the strong character development that has made the show a fan favourite. The Secret Garden is a standout episode that fully embraces the show's themes of friendship, loyalty, and the struggle for power in a world where humans and demons must coexist.