Code Geass: Hangyaku no Lelouch/Stage 4

After a cutscene featuring the Commander-in-Chief of the Imperial Army, Cornelia li Britannia, the point of view will switch back to Lelouch in Ashford Academy. Innocently enough, he's having a conversation with his sister, Nunnally. This is until C.C., the girl who gave Lelouch his Geass, surprises Lelouch with her presence. Nunnally questions Lelouch on who the mysterious girl is while C.C. jokes around by making their Geass contract sound more like an engagement. This gives Nunnally the idea that Lelouch and C.C. are involved romantically, and you must come up with an answer which hides the truth effectively. Your options are: All answers will lead to a continuation in the story, except for the second, which leads to a game over. Afterward, Lelouch and C.C. go to Lelouch's room, where they discuss their next move. Eventually, the cutscenes will end and you'll be given control of Lelouch on the field map. Head up to the roof to meet up with C.C., where Lelouch scolds her for walking around the academy and the two discuss Lelouch's next move, now that he has revealed himself to the public as the enigmatic Zero. Lelouch decides he will change the empire through force using a rebel organization which he will lead: the Order of the Black Knights. After the discussion, you'll have to choose the people you want to take on your first official Black Knight mission.
 * そうだよ (Yeah)
 * 新しいお母様だよ (She's your new mother)
 * ブリタニアをぶっ壊す！ (I'll destroy Britannia!)
 * ちがう (No)

Forming the team
Kallen Stadtfeld will be on the team by default, so all you have to do is pick two eligible knights to accompany her. Kaname Ohgi and Shinichirō Tamaki would be the safest choices, since you've fought with them before. At this point, they should be at levels decent enough to combat the higher level soldiers present in this stage. You should also have an easy time if Tamaki and Ohgi left behind some skill points to spend on special moves. If you're looking to challenge yourself, though (or just looking to balance out the knights in terms of power) you can take a couple of the greener recruits with you. Kallen can act as some heavy support for the team by using her skills (especially if you left some skill points behind from the previous stage), and the level 1 knights can grab the experience easily by landing the finishing blow on the weakened soldiers.

Carrying out the mission
As he has done before, Zero will act as your guide, telling you which way to go whenever you reach a fork. The first set of directions is west, north, east, and south into a couple of soldiers. Their backs are facing you, so Zero directs you to initiate a surprise attack and dispose of the unsuspecting soldiers quickly. Do as he says and you're looking at a fast battle. Surprise attacks give you the advantage of two turns per party member before an enemy even touches a knight. Start off by getting Kallen (or Tamaki/Ohgi if they're in your party) to use a skill, then have the other two party members attack the same soldier. Try to get rid of the second soldier before he gets his turn, but if you don't manage to, you still have a shot at a clean win. If Kallen manages to dodge the enemy attack (they usually target the highest-leveled party member), kill him on your third turn and you'll get the experience without any lost health. After the battle, Zero will give you more directions into another surprise attack, and then another. Repeat the battle strategy (your party should regain their lost skill points with each attack/kill) for some more flawless victories. After a little scene from the point of view of Cornelia, Zero will direct you into a couple of new enemies. These shouldn't give you any more of a problem than the standard mech though. Defeat them and walk north a bit for a scene. Euphemia li Britannia, the sister of Cornelia, is unexpectedly attacked by Jeremiah Gottwald (who still happens to be under the effect of Lelouch's geass). Fortunately, Suzaku Kururugi comes to the rescue in his Lancelot. Afterward, follow Zero's directions once more into another couple of unsuspecting soldiers. After you finish them off, take the path to Cornelia. Zero confronts her, and Kallen jumps in to defend Zero, initiating a battle. You'll be fighting against three soldiers this time - one more powerful than the others. Focus on using skills (either use level 1's and level 2's or attack until you get a level 3) and make everyone focus on the stronger soldier until he's gone. His attacks are powerful and tougher to dodge, so it's better to take him out early. Once the battle's over, enjoy the stage's ending cutscenes and gear up for Stage 5.