In Gerald's ninth mission where you need to defend Hironeiden's castle wall from the enemy, if you defeat the huge onslaught of enemies, you will get an alternate cutscene instead of the standard one where Rupert arrives with reinforcements.

Include a Sapper or Pyrotechnic unit and set normal traps near the wall that needs to be defended. Place one complete line of traps going north and south and in places where enemy units tend to cluster. The traps will ward off enemies long enough for your combined unit of infantry (or knights) and Paladins to destroy all the enemies for the alternate cut-scene.