Hina Tsurugi and her family have just moved to a quaint seaside town. Hoping to savor the sight of the peaceful ocean, Hina stumbles upon a girl named Yuuki Kuroiwa—an upperclassman at her new school—who invites Hina to join her in fishing. Hina reels in an octopus, which falls onto her; being afraid of bugs and big creatures, she panics and begs Yuuki to remove it from her. Yuuki sees this as an opportunity to force Hina to join the school's Breakwater Club—a club where members gather, catch, and eat various types of marine life as their main activity. Although her attempts to refuse to join fail, Hina slowly begins to discover the hidden joy in fishing. Her view on the sport changes, now looking forward to all the delightful experiences she can take part in alongside her fellow club members.

Ikebukuro is home to many different businesses and gangs. This includes Makoto Majima: the infamous troubleshooter who mediates between warring factions. Makoto knows all of the ins and outs of the bustling Tokyo district and strives to maintain peace alongside the G-Boys, who assist Makoto in his troubleshooting endeavors. Led by the charismatic and ruthless Takashi Andou, the G-Boys is the most influential gang in all of Ikebukuro. However, when the new faction Red Angels begins to move in on the G-Boys' turf, immediate tensions rise between them. With numerous enemies scattered around and within the G-Boys, navigating through the streets becomes more difficult for Makoto. While continuing to troubleshoot problems, he slowly unravels a plot that may trigger an all-out war and threaten the entirety of Ikebukuro.

Yuu Izumi leads a high school life filled with one mishap after another. No matter how improbable the situation, unfortunate events strike him at every turn. In possession of such terrible luck, Izumi enters his second year with a single wish in mind—to spend more time with his affectionate girlfriend, Micchon Shikimori. Cute, athletic, and caring, Shikimori is immensely popular at their school. But since they began dating a year ago, Izumi has witnessed a surprising side to his otherwise adorable girlfriend: when the need arises, she turns incredibly cool! His misfortunes are easily avoided when she is there to protect him with an awe-inspiring look on her face. Charming in every way, she never ceases to make his heart skip a beat. Unfortunate as he may be, Izumi is sure to see his days of bad luck end thanks to the cute yet cool Shikimori.

After witnessing the death of her family at the hands of bandits, Unchou Kan'u has devoted her life to protecting the innocent by exterminating any group of bandits she comes across. Over time, Kan'u's deeds become famous throughout the land—even if she herself remains unknown. During her travels, she runs across a young girl, Chouhi Yokutoku, whose parents suffered a similar fate as Kan'u's. Finding companionship through their similar pasts, the two girls take a vow of sisterhood and continue to wander the land, determined to bring peace to wherever their journey takes them. During Kan'u and Chouhi's journey, they meet and travel with several people who are sympathetic to their cause, such as the noble Chouun Shiryuu, the headstrong Bachou Mouki, and the calculating Shokatsuryou Koumei. From problems with local lords to groups of ravaging bandits, Kan'u and her friends do what they can to make life a little easier for those in need, wherever they may be.