After stopping the invisible foes in Cyrkensia, you seek the Rainbow Sage in Notre Sagesse.
Rout the Enemy
This map should be familiar if you played Conquest. However, this time you do not have to defend any tiles, making it a bit easier.
You will have to defeat all of the enemy units to end the battle.
Elise can talk to Charlotte and Benny, who are in the southwest and southeast of the map. Be sure NOT to get into their attack range before Elise talks to them, because otherwise they will attack, and you might defeat them before you can recruit them. Elise can NOT talk to Silas, and neither can Corrin, so don't bother.
There are four houses that you can visit, and all four will give you rewards, so be sure to do that before the Outlaws can reach them.
There is a Fire Orb near where your units start, and there are a couple of Ballistas nearby as well, but since you are trying to rout the enemy, they aren't going to be of that much use once you deal with the first wave of enemies.
Elise can pair up with a flying unit to send her to Charlotte and Benny more quickly. Or you can just take your time killing enemies as you clear a path for Elise.
There are some walls in this map that you can break by attacking them. Your enemies might try to break them first.