Post Kids

In a near future where a plague has exposed conflicts and economic disparities between city-states, a new generation of children, born with antibodies but ridiculed as "zombies" due to their blue skin, have joined the "Universal Postal Foundation," which handles deliveries both within and outside cities. One of them, Fumito, gets caught up in a mysterious designated delivery request!? A post-apocalyptic delivery action story! (Source: Shounen Gahosha, translated)