Seeking a means to gain an advantage over the Turtles, the Dragon Lord sends Wick and some Rank Dragons out into the city to gather the rare ingredients needed to make the ancient Serum of Invincibility. Once ingested by the Rank, the now-invincible warriors are sure to triumph over the TMNT... Using his "turtlefied" eye-in-the-sky satellite, Donatello traces a group of Dragons into Chinatown. Splinter believes that the Turtles should be defensive rather than offensive, so the TMNT merely watch the actions of their enemies rather than engaging them in battle. In doing this, the sensei hopes to spot a weakness in the powerful foes. Raphael, however, disagrees and sets out by himself to Chinatown in order to kick Wick and Dragon butt... but instead ends up having to be rescued by his friends. Meanwhile, the Dragon Lord was only able to gather enough ingredients to make Serum for six warriors --- far short of his goal to turn all of his minions into super soldiers. And so DL sends off another team of the Rank to the Bronx Zoo, as the rare ingredients that he needs comes from the powdered bones of some of Earth's most endangered species. Fortunately, the TMNT are on the scene to thwart the Dragons. During the fight, one of the Rank ingests one dose of the Serum of Invincibility and, up until he panics and flees, proves himself to be nigh invincible! Although the skirmish at the zoo is won by the Turtles, the Dragon Lord vows to continue his quest for the ingredients to make all of his warriors invulnerable.