Everyone knows the Squid Sisters. Callie and Marie are household names within inkling society, as their music touches the hearts and souls of all who listen. But there are very few who know the real story of how their bond grew from cousins to that of sisters. Immediately after the cousins win first place in Inkopolis's first annual Youth Folk-Singing Contest, they paint themselves as potential upcoming stars...and targets.

Well, would you look at that? The Great Zapfish has disappeared once more. At this point, that's not a shocker in the city of Inkopolis. What is shocking is that multiple idols have suddenly vanished alongside the Great Zapfish. Even the Judds have gone missing! With so many big players vanishing from the scene, Inkopolis has devolved into a crime-riddled city. The streets are unsafe, and gangs rule almost every part of town. With Inkopolis in such a state, the people will find their heroes in the form of two octoling brothers, Sal and Cal. Both have no redeeming qualities, and neither have achieved an admirable feat. They're a bunch of nobodies! Yet, they're Inkopolis's best shot at restoring order, as well as weeding out the sinister evil that lurks within...