Along Dallas's Trinity River, Jakub Vagner searches for a true Texas titan, the alligator gar. The gar are known for their bony skulls, armorlike scales and piercing teeth, but their natural weapons can't protect them from overfishing and environmental changes. Jakub's mission is to help scientists tag several fish for data and seek out a huge gar to catch and release, hoping to prove that big specimens are still out there. Jakub lands a true behemoth a 125-pound, 6-foot gar!

Jakub Vagner goes head-to-head with a prehistoric fish that survives today the white sturgeon. With a skeleton of cartilage and rows of sharp plates called scutes around its body, a white sturgeon is able to grow to more than 1,500 pounds. However, this extraordinary species has suffered a decline in population because of habitat destruction and overfishing. Jakub joins local experts on a mission to catch and tag white sturgeon to aid the species survival.