The seventh volume of Sankichi Hinodeya’s Splatoon manga starts the Octo Arc, which is the adaptation of the Octo Expansion from Splatoon 2.
This volume contains chapters twenty-four through to twenty-seven of the story, as well as a bonus manga.

Front cover of the seventh volume of Splatoon, featuring Goggles and Eight
Inside an underground facility connected to the Deepsea Metro subway system, Goggles and Team Blue must pass a series of tests to discover the four “thangs” that will open the door to a fabled Promised Land.
As this volume of the manga adapts the Octo Expansion, Goggles finds himself accompanied by an amnesiac Octoling who he calls Eight. Over the course of the story, he is reunited with the rest of Team Blue as well. The Octo Expansion is very much a single player experience on the Nintendo Switch, but the manga has an established cast to focus on.
The general idea is the same as in the game, though; complete a series of challenges and collect the four thangs. If you’ve played the game, you’ll no doubt recognise some of the challenges that have made their way into the manga.
Pearl and Marina also get to do something other than commentating matches in this volume, which is nice. Admittedly they are only in a support role whilst the story focuses on Goggles and Eight, but we actually get more of them than in any previous chapters. Also, knowing what I know about the Octo Expansion, Off the Hook are going to be fairly important in the next volume.
The Octo Expansion may have a darker tone compared to the rest of Splatoon 2, but that doesn’t stop the manga from having its ridiculous moments – lampshaded by the characters whenever Team Blue do something ridiculous. Can’t forget the naked Inkling (and now Octoling) gag that never seems to disappear, either. That one ran its course long ago.
As much as I dislike that one running gag, the manga is an enjoyably silly read. Splatoon fans will most likely get a kick out of it, and its nice to see that Pearl and Marina are getting a bit more to do with this volume.