Equally charming and stern, Heine Wittgenstein is a brilliant man who commands respect, despite his short, childlike stature. Thus, the king of Grannzreich has called upon Heine to undertake a daunting task that has driven away many before him—become the new royal tutor to four princes who are in line for the throne. The four heirs each have very distinct and troublesome personalities: Licht, the flirtatious youngest prince; his immature older brother Leonhard; Bruno the studious third prince; and Kai, the oldest of the four and the most reserved. Hilarity ensues as Heine attempts to connect with each of the princes in order to groom them for the throne. However, Heine's mysterious past and dark undercurrents in the present may threaten the harmony within the kingdom. [Written by MAL Rewrite]

Shogi, a Japanese game similar to chess, is one of the most popular board games in the country, played by everyone from children to the elderly. Some players are talented enough to take the game to a professional level. The title of Ryuuou, meaning "the dragon king," is only awarded to the person who reaches the pinnacle of competitive shogi. Yaichi Kuzuryuu has just become the youngest Ryuuou after winning the grand championship. However, the shogi community is unwelcoming to his victory, some even calling him the worst Ryuuou in history. Moreover, he forgets about the agreement he made with Ai Hinatsuru, a little girl he promised to coach if he won. After she shows up at his doorstep, he reluctantly agrees to uphold his promise and makes Ai his disciple. Together, they aim to improve and exceed the limits of their shogi prowess: Ai, to unlock her hidden talents; Yaichi, to prove to the world that he deserves his accomplishments. [Written by MAL Rewrite]

Humans have been polluting the ocean for a long time, carelessly pouring their garbage and desecrating the waters that many creatures call home. The denizens of the sea have suffered at their poisoning hands. Finally, one certain squid has had enough and vows to punish the humans' selfish actions. Possessing all the fearsome abilities of a squid such as powerful hair-tentacles, the ability to spit ink, and even use bioluminescence at will, Ika Musume takes it upon herself to rise from the depths of the ocean and exact revenge upon humanity! She surfaces at a certain Lemon Beach House, a restaurant managed by the sisters Eiko and Chizuru Aizawa. Thinking them to be an easy first step toward world domination, she immediately declares war against them, only to find out that she is, quite literally, a fish out of water! To make things worse, she destroys a part of a wall of the beach house in an attempt to flaunt her squiddy superiority and is consequently forced into becoming a waitress to pay the repair costs. Beached for the time being after tasting a thorough defeat at the hands of the Aizawa sisters, Ika Musume is forced to put her plans for world domination on hold. Despite these setbacks, Ika Musume soon finds herself right at home in her unexpected position as Lemon Beach House's newest employee. Wacky and hilarious, Shinryaku! Ika Musume follows her brand new life on the surface as she makes precious memories and meet lots of new people. With her newfound acquaintances, Ika Musume is looking to take the world by storm, one squid ink spaghetti at a time! [Written by MAL Rewrite]

After regaining her squid-like abilities, Ika Musume plans to resume her self-appointed mission to destroy all of humanity. However, her carefree job as a waitress in the Lemon beach house meant she cannot help but laze around during her spare time! On top of that, she is saddled with many problems, such as being pursued by a group of alien-obsessed individuals and catching the interest of a crazy girl. Picking up after the conclusion of the first season, Shinryaku!? Ika Musume follows the hilarious life of Ika Musume as she plots her next invasion of the surface world. [Written by MAL Rewrite]