Walking along the path to Dawnguard Fort you discover the Gardens of Icarus Emporium. You enter. You work your way to the Bookseller within the shopping mall. The Fence Khajiit offers many selections of books and spell tomes; you buy one that interests you -- Icarus. What is Icarus? Icarus is the Summonable Dragon (Actually 2 as this is an undefined Glitch I discovered). Why summon a Dragon? You may need to acquire Dragon parts (scales, bones) or clear out a Bandit hideout.
M7 :) 2016.
Uses Dawnguard / Hearthfire DLC.