Each episode introduces a new opponent for the caveman and the T. rex to overcome, be it giant bats or woolly mammoths, or learning to work together as a team. The "lessons" out of every episode are no different than what you'd learn from any empathetic kids' show, but Primal is not for youngsters. Death is everywhere in this version of the past, bloody and violent and horrible. Every day of survival means a decision to kill something, either so you can eat or so that you won't be eaten. There's a lot of blood, and some very shocking moments, but the show never takes any sort of glee in the violence it shows, nor is the gore ever gratuitous. It adds to the overall effect of the show, lending a stark maturity to a story of dinos and cave people more likely to be thought up by a 6-year-old.
Underneath the flashy fight scenes, though, the show is more than anything a very deft and cutting exploration of grief. The third mammoth-centric episode (naturally) is entirely about the process of mourning your dead, taking cues from modern-day elephants' tendency to carry the bones of their lost family members. Only an animator like Tartakovsky, whose characters always have a surprising array of emotional expressiveness, could make the relationship between a caveman and a dinosaur so compelling. The second episode, thrillingly, includes a callback to one of the best scenes in The Clone Wars: a wordless fight between two opponents in the middle of a rainstorm. Like his early work, it's Primal's moments of stillness that turn it into something special.