A dinosaur named for the word "tasty" learns to love the thing he's biologically wired to eat. Heart doesn't ask you to suspend disbelief about nature, it asks you to watch a father and son tear each other apart anyway, then choose each other. The budget is rough and the plot frays at the edges, but the moment Umasou realizes what his father actually is, you stop caring about either of those things.
A young tyrannosaurus raised by a gentle herbivore mother discovers the brutal truth about his own predatory nature, sending him fleeing into the wilderness alone and terrified of what he might become. In his escape, he stumbles upon an unhatched egg and impulsively names the creature inside "Umasou," meaning delicious. When the egg cracks open to reveal a baby ankylosaurus, the newborn immediately bonds with Heart as his father figure, creating an impossible situation. Heart must confront everything his adoptive family taught him about kindness and compassion while standing before a living reminder that his instincts demand meat. This tension between who Heart wants to be and what his body demands becomes the heart of their relationship. As the two grow closer despite their fundamental differences, their bond challenges every rule of survival in a prehistoric world where predator and prey should never share affection. What emerges is a story about love transcending biological fate, where a dinosaur's greatest struggle isn't against other creatures, but against his own nature.