Tunnel Vision is the fourth episode of DreamWorks Dragons: Defenders of Berk.
When the town's well runs dry, Hiccup and Toothless discover a group of baby Whispering Death dragons living in the tunnels underneath, planted there by Alvin
The riders are chasing Gobber through town in order to forcibly bathe him, for his own good as well as that of the village, since he refuses to take a bath of his own accord claiming that Vikings are supposed to smell bad. Just when they succeed in getting him into the wash tub Stoick learns that their well has dried up early. Recognizing the seriousness of the situation Stoick initiates a rationing of water.
Hiccup also makes plans to help in the shortage: Ruffnut and Tuffnut will take the wash tub and Barf and Belch and go to Lars Lake to retrieve as much water as they can, while Astrid and Snotlout will go to the mountain springs and bring back as many canteens of water as Hookfang and Stormfly can carry, meanwhile Hiccup and Fishlegs will investigate why the well dried up in the first place.
Having Meatlug lower him into the well Hiccup learns that until very recently the well had plenty of water. Unfortunately a distracted Meatlug accidentally cuts the rope but thankfully Hiccup is saved by Toothless at the cost of trapping both of them underneath the village. Despite his father's insistence to stay put Hiccup begins exploring the underground network of tunnels and soon learns of Outcast planted Dragon eggs.
Worst yet the Dragon and Rider are attacked by a trio of Juvenile Whispering Deaths (which as it turns out are even more fearsome and unpredictable then their adult counterparts due to not having full control over themselves) which he is able to lose them sending them to the surface in the process, to which Hiccup and Toothless follows them. On the surface the riders are jumped by the Juveniles and begin breaking them up to fight them more easily.
Finally reaching the surface Hiccup retrieves his shield and begins using it to herd all the Whispering Deaths. Just when they seem successful an even more ferocious Whispering Death sub species that Tuffnut dubs a Screaming Death appears: far larger than others, even more terrifying, and has full control over its spines and tunneling. While the other riders fight of the recalled trio Stoick and Hiccup attempt to fight off the Screaming Death.
Hiccup soon learns that unlike it's smaller counterparts the Screaming Death is actually attracted to bright light, and uses this to his advantage by tricking it into smashing into several rock faces with his shield eventually grounding it. The Whispering Deaths take their wounded leader and retreats, and once cleanup at the village begins Hiccup learns that in all the commotion the dragons dug a new well, leading to Gobber getting his long awaited bath.
Hiccup is still left concerned, although he isn't training dragons yet Alvin is still using them as weapons. Worst yet Whispering Deaths have a bad habit of returning to their birthplace as adults and claiming it as their territory meaning that the Screaming Death and it's pack will soon be back.