In a world covered by an endless sea of sand, there sails an island known as the Mud Whale. In its interior lies an ancient town, where the majority of its inhabitants are said to be "Marked," a double-edged trait that grants them supernatural abilities at the cost of an untimely death. Chakuro is the village archivist; young and curious, he spends his time documenting the discovery of newfound islands. But each one is like the rest—abandoned save for the remnants of those who lived there long ago. For the first time in six months, another island crosses the horizon, so Chakuro and his friends join the scouting group. During the expedition, they find vestiges of an archaic civilization. And inside one of its crumbling remains, Chakuro discovers a girl who will change his destiny and the world inside the Mud Whale as he knows it. [Written by MAL Rewrite]

The rigorous city life of China, while bustling and unforgiving, contains the everlasting memories of days past. Three stories told in three different cities, Shikioriori follows the loss of youth and the daunting realization of adulthood. 

Though reality may seem ever changing, unchangeable are the short-lived moments of one's childhood days. A plentiful bowl of noodles, the beauty of family and the trials of first love endure the inevitable flow of time, as three different characters explore the strength of bonds and the warmth of cherished memories. Within the disorder of the present world, witness these quaint stories recognize the comfort of the past, and attempt to revive the neglected flavors of youth. 

Japan, 1955: Mario Minakami has just arrived at Shounan Special Reform School along with five other teenagers who have been arrested on serious criminal charges. All assigned to the same cell, they meet older inmate Rokurouta Sakuragi—a former boxer—with whom they establish a close bond. Under his guidance, and with the promise that they will meet again on the outside after serving their sentences, the delinquents begin to view their hopeless situation in a better light. Rainbow: Nisha Rokubou no Shichinin follows the seven cellmates as they struggle together against the brutal suffering and humiliation inflicted upon them by Ishihara, a sadistic guard with a grudge on Rokurouta, and Gisuke Sasaki, a doctor who takes pleasure in violating boys. Facing such hellish conditions, the seven inmates must scrape together all the strength they have to survive until their sentences are up; but even if they do, just what kind of lives are waiting for them on the other side? [Written by MAL Rewrite]