When you are taken captive by the Elves during Gain New Allies, you will be in the Elven Kingdom. Talk to Stan to get this sidequest, who asks you to defeat the She-Ogre to get his iPhone back. Go to Stan's house and head upstairs, then go through the second door to begin the fight.
Shelly, or the She-Ogre, is quite strong and has a lot of HP, but she's only immune to stun, so if you have the means to inflict the other ailments on her, do so. Cherry Bomb, when she has buffed her attack, can do a lot of damage and possibly KO one of your characters if they have almost full health.
After defeating her, the quest will be over and your reward is XP and Stan becoming your Facebook friend.
