"DreamWorks Dragons" is the Cartoon Network TV series follow-up to the Oscar-nominated 2010 movie "How to Train Your Dragon." The second season the dragon riders become "Defenders of Berk," a follow-up to the first season, "Riders of Berk."
"Defenders of Berk" begins where "Riders of Berk" leaves off. The people of Berk have adjusted to life with dragons, but their settlement is threatened by outside forces. They now are ready to defend themselves against Alvin and the Outcasts ("Live and Let Fly"), but they are surprised at Alvin's tactics and the continue to learn more about dragons--new species and even their own mounts. Of course, the good lessons include the importance of each team member and teamwork.
Fishlegs and his Gronckle, Meatlug, accidentally discover a new metal alloy which is lighter and sturdy ("The Iron Gronckle"). Fishlegs helps Gobber at a time when Meatlug's slow flight pace is criticized by the rest of the dragon flying gang. Ultimately, Hiccup and the others realize that Fishlegs goes slow enough to study the geography and map out their discoveries. They want him back on their patrols and a few new tools are made with the Gronckle iron that Fishlegs has no idea how to make again.
While on a training exercise devised by Astrid ("The Night and the Fury"), the Defenders of Berk are on Dragon Island and run into Dagur the Deranged who is not focused on dragon hunting and Dagur learns their secret--they don't hunt dragons, the people of Berk train them.
Alvin and the Outkasts haven't gone away and they bring Berk a present that causes their well to run dry ("Tunnel Vision"). At the same time, Hiccup and his friends meet Whispering Death hatchlings and learn about a new type of dragon: Screaming Death ("Appetite for Destruction").
Snotlout learns that sometimes he knows better than his father when his dragon becomes sick and they must find a cure for an exhaustion sickness ("Race to Fireworm Island"). Toothless also becomes sick during this season from eel pox ("The Eel Effect"), but don't let that put you off of eating eels. The past comes to haunt Astrid when she seeks to find a ghostly dragon that caused her uncle to freeze in terror ("Fright of Passage"). She's fighting for her family honor, but needs the help of her friends. Other dragons include the swift Speed Stingers ("Frozen" without the musical talents of Idina Menzel) and the lightning-powered Skrill ("A View to a Skrill").
Throughout, the threat of Alvin and the Outkasts, Dagur and Mildew is always in the background until the last two episodes in which Hiccup learns something about his father and Hiccup and Snotlout come to a better understanding of each other's strengths and weaknesses. In both seasons, we are reminded that Hiccup is also in training to some day be chief.