Stranded on a violent planet with a group of other random droids, we finally learn how C-3PO came to have his red arm in The Force Awakens.

While this might not be quite as action fueled as some other one-off comics, the plot is surprisingly deep. It discusses the idea of whether droids can form emotional connections and if they need their memories to be who they are, also bringing up how 3PO had his memories wiped at one point in time.