"River of Tears" is an episode of the animated series.
Jimmy enters the secret lair under the Dragon Dojo and asks Billy, who is at a large computer, if he has managed to crack the Shadow Master's communications code, but so far he hasn't. Billy is doing this to find out the reason of a sudden burst of Shadow Warriors' activity.
Meanwhile, Sickle is running urban style gladiatorial games at an empty dam, both running bets and seeking for potential recruits. Some homeless kids at a nearby tunnel watch the fights and one starts imitating the moves. The kids' homeless guardian, Vortex, defeats the kid without harming him and reminds him to not fight dirty like those men. Sickle watches Vortex and notices that he has good moves. After Vortex sends the kids to sleep, Sickle approaches him and asks who thaught him. Vortex claims he has no training, but Sickle doesn't believe him and they fight, after which Sickle tells that Vortex will fight in the games the next day, or else the kids will be taken to the Shadow Dojo.
Vortex finds police officer Marian and asks for her help. Next day, shortly after Vortex enters the fight he was forced into, there's a police raid. Vortex is arrested to kep appearances. When Sickle reports at the Shadow Dojo, Shadow Master instructs him to continue with the tournament, and to find the informant who talked with the cops, they will use a rat to catch a rat. When Vortex is freed and thanks the help against the Shadow Warriors, a robotic rat sees him and shows it to Shadow Master, who contacts Sickle.
At the Dragon Dojo, Billy finally manages to crack the code and hears Shadow Master telling Sickle that they found out Vortex was the informant. Billy and Jimmy take the Dragon Cycle, and when Jimmy asks who is Vortex, Billy replies that he's a lad Marian told him about.
Billy and Jimmy arrive to Vortex and the kids' box homes. When the Lee brothers tell Vortex that they want to keep the kids safe at the Dragon Dojo, Vortex thinks it's just like Sickle wanting to take them to the Shadow Dojo, so he fights the brothers. Billy gets fed of it and leaves, with Jimmy following and noting that the hothead role was reversed this time. Right after the Lee brothers leave, Sickle arrives with Trigger Happy and some henchmen. Vortex is too fast to Trigger Happy's aim, but Sickle pins Vortex down, which makes Vortex have a flashback of a relatively younger Sickle. The Lees notice the fight and transform into their masked forms before going to help Vortex. After Trigger Happy and the henchmen have been defeated, Vortex goes after the kids, and Sickle throws a smoke grenade to the Double Dragons in order to keep them from seeing where did Vortex go and pursues him. Vortex sees Shadow Warriors taking the kids to a helicopter, and Sickle tells him that they will let the kids go if he wins the tournament.
The following day, Vortex defeats his forst opponent, Basher, and Shadow Master, who watches from a monitor at the Shadow Dojo, notices something familiar about Vortex's style. Right then, Countdown calls Shadow Master to tell him that a police squad is searching the place where the kids are held, which Shadow Master finds convenient as they will get rid of the kids and the police at once, so he orders Countdown to blow the dam up. The Lee brothers once again intercept the communication, so they transform into the Double Dragons.
Vortex is tired of facing so many rivals in a row, but he reminds himself to fight with honor and defeats Piker, another opponent. The Lee brothers arrive to the dam in the Dragon Cruiser, but before they can search for the kids, Countdown blows the dam up and they must outrun the water. Jimmy notices the kids, so they stop to free them, Billy cuts their cage bars and gets them all into the Dragon Cruiser, which speeds upside to escape the water just in time. Then Marian arrives with the police squad, but they are spied by the robotic rat.
Vortex faces his twelfth and last opponent, the four-armed Repo, but after Vortex defeats Repo, Sickle declares that the tournament isn't over, and declares himself Vortex's last rival. Sickle draws his weapons, so Vortex also draws his smaller blades. During the fight, Vortex has the flashback about a younger Sickle again. Before there can be a winner, Shadow Master appears and tells Sickle to leave Vortex to him. Shadow Master separates his weapons and shoots Vortex with the sword, while asking who trained him, something that Vortex remembers just then. The Lee brothers arrive and Jimmy throws the remains of the robotic rat to Shadow Master. They exchange sword blasts, and Shadow Master leaves. Sickle reminds them that he's still there, so Jimmy blasts him and then the Double Dragons go check if Vortex is alright.
Vortex tells the Lee brothers what he remembers: Back when he was a kid, a man stayed with his family for a while and taught him martial arts, but something happened and the man had to go. Then, Shadow Master came and Vortex had to run away from the younger Sickle while the Shadow Warriors burned his house down. Vortex says he was a coward then, and a loser now since he lost to Shadow Master. Billy assures Vortex that he's no loser, as he had to face twelve men, plus Sickle and Shadow Master. Then they knight Vortex as a Dragon Warrior.
Later, Billy asks Vortex the name of who taught him martial arts, and Vortex replies that his name was John Lee. Jimmy asks if John survived, but Vortex doesn't know. Neither of them met their father, but Billy is sure that he would be proud to know that they are fighting the forces of evil together.