Josh is determined to capture the Blood Claw Bandit and use the reward money to help fix his family's ranch, especially after Josh's beloved triceratops, Charge, is stolen.
While the sheriff is away, crooked, businessman Malachi Wilks and his stegosaurus workers try to build a railroad through Trihorn Valley, with only Josh and his friends standing in his way.
With the help of his friends Sam and Abi and his trusty Dino Cowboy Diary, Josh dreams of roping a wild Triceratops and maybe become the next great Dino Rider.
After recording the facts in his Dino Cowboy Diary about the biggest dinosaur in existence, Josh brings his friends Sam and Abi along on his mission to capture one.