The Big Brawl, Part 1.As he does every three years, Master Splinter mysteriously goes off and leaves his sons for a few days. This time, however, curiosity sets in and the Turtles follow him through an interdimensional gateway, ending up in a nexus between dimensions, where the multiverse's greatest warriors meet to duel each other in tournaments. Through an old friend of Splinter's who had battled him in the qualifying round, the Turtles learn that Splinter was the past Battle Nexus champion, who defeated an evil dragon named Drako in the final round despite breaking his leg. Despite his discontent, Master Splinter hesitantly allows his sons to enter the competition.