Ep 1. Summer Break! Off to the Underworld!

High School DxD is an anime series that chronicles the misadventures of Issei Hyodo, a perverted high school student who is killed by a girl on his first date. He’s later resurrected as a devil by Rias Gremory, a beautiful and powerful demon, to serve as her devil servant. The series is full of ecchi moments, fan service, action, and comedy. Season 3 of High School DxD begins with episode 1 titled "Summer Break! Off to the Underworld!"

The episode starts with Issei and his friends enjoying their summer break by the poolside. While lounging around, Asia suggests that they should visit the underworld for their summer break, and everyone quickly agrees. They want to explore the different areas of the underworld and experience new things, but their excitement is short-lived when they learn that the underworld is in chaos due to multiple terrorist attacks happening.

Issei and his friends soon find themselves in the presence of Sirzechs Lucifer, Rias' older brother, and the current leader of the underworld. Sirzechs informs them that the terrorist group responsible for the attacks is called 'Khaos Brigade,' which aims to kill the current leaders of the underworld to cause chaos and confusion. As the situation becomes precarious, Sirzechs stresses the need for a strong defense mechanism to counter the coming danger. The leaders of the underworld opt to use the opportunity provided by the young devil servants, including Issei and his friends, to train them in combat and make them more powerful.

The devils undergo training in preparation for the forthcoming battle, and the first task at hand is to defeat three powerful monsters in different locations within the underworld. Rias, who is a high ranking devil, along with Azazel, Ravel, and Akeno, are tasked with defeating a powerful Cerberus in the deeper parts of the underworld. On the other hand, Issei, Koneko, and Gasper are tasked to find and defeat a powerful Grendel and Basilisk in a different area.

As the young devils move into the deeper parts of the underworld, they find themselves battling hordes of demons and encountering dangerous situations in the process. Issei, Koneko, and Gasper soon find themselves under attack from a group of powerful demons, who are protecting the Grendel and the Basilisk. However, they manage to overcome the demons and the two powerful monsters through their strength, determination, and commitment. Meanwhile, Rias and her team also battle fiercely with the Cerberus and emerge victorious, leaving them all more powerful after the thrilling battles.

The episode ends with the young devils returning to the surface, their training done, and fully aware of the dangers that lie ahead. Sirzechs bids them farewell and advises them to continue to work hard for their growth. The young devils leave the underworld with new knowledge, new allies, and an understanding that the battles ahead are going to be brutal. They are also more determined than ever to protect their loved ones and the underworld they call home.

In conclusion, High School DxD Season 3 Episode 1 is a full action-packed episode providing a launchpad for the forthcoming battle. The mission of the young devils reflects how committed they are to serve as protectors of the underworld, and the episode ends leaving viewers wanting more.