Set in a world where a devastating virus has turned most of the population into blood-thirsty predators, Crimson is a post-apocalyptic re-envisioning of the classic Little Red Riding Hood fairy tale. The story unfolds through two characters - a lone special operations soldier who has been separated from the rest of his team, and a young girl who he encounters while trying to survive the hostile yet desolate landscape. Although they are wary of each other in the beginning, the two eventually form a close bond. The soldier soon realizes that he must protect the girl from the dangers lurking around them - in the only way he knows how. But as time moves forward, it becomes apparent that he must not only teach the girl how to defend herself, but also prepare her for the inevitability that he cannot protect her for much longer.