Second season of Nanatsu no Taizai: Mokushiroku no Yonkishi.

As a young child, Takashi Natsume believed his ability to see youkai to be nothing but a curse. Now a high school student, Natsume has managed to heal from his old wounds and form unbreakable bonds with humans and youkai alike. Natsume's newfound friendships—including the one with his spirit bodyguard Madara, nicknamed Nyanko-sensei—are often interlaced with his duty to return the names of the spirits written inside the Book of Friends, his late grandmother Reiko's keepsake. While more remarkable youkai reach out to him, Natsume discovers that he still has much to learn about the world that surrounds him.

For blasé college dropout Tsunehiro Sasaki, life has become hopeless. After failing to enter a top university, he has lost all his money trading on financial markets and is now critically indebted. To add to his misery, he learns that he only has at most two years left to live due to an incurable disease. The trajectory of Tsunehiro's life suddenly changes after a group of amateur fishermen saves him from drowning as he was trying to escape from a trio of creditors. While Takaaki Tsutsujimori pushes Tsunehiro to work at the group's workplace—a convenience store that doubles as a fishing shop—Hana Ayukawa tries to share her love for fishing. Although the attempts of the joyful group of anglers initially prove unsuccessful, Takaaki urges Tsunehiro to take a fresh start in life, and the young man eventually accepts the fishing enthusiast's assistance to pay off his debts. As work, friendships, and an unfamiliar hobby all suddenly find their way into his life, Tsunehiro must find the strength to change his ways if he wants to make the best of his remaining time.

As dungeon-like treasure vaults started appearing throughout the land, more and more people began signing up as treasure hunters—risking their lives to obtain the vast riches and ancient relics inside. In the imperial capital of Zebrudia, the top hunter party is the Grieving Souls—a group of six childhood friends led by Krai Andrey, who is thought to be the strongest of them due to having a reputed wide array of skills. However, Krai actually has no special talent. His accomplishments are actually the result of his friends being overpowered. Krai has repeatedly attempted to leave the party out of fear his lack of aptitudes would one day cause his companions' downfall. Nevertheless, everyone around Krai thinks differently, making him feel obligated to remain the group's leader.