When you are spying on the Highland camp, at the end you get attacked by Highland soldiers. After you beat them, Jowy will hold them off while you run to Nanami. When you reach her, you fight more Highlands(use Bright Shield to defeat them easily). After that she asks where Jowy is. Reply ".....", and more Highlands appear. After the battle she asks you again. Keep replying "...." to fight more Highlands every time. Keep using Bright Sheild until it runs out, then use Flaming Arrows from the fire rune. After the runes run out, use Family Attack on the one with the spear and just attack the rest.(if you're not around level 20 this can be difficult)Anyway, the first couple battles should give close to 1000 experience each. Keep doing that until your levels are pretty high(or they stop giving you less than 100 experience).