Heroes of Might and Magic III: The Shadow of Death/New Beginning

Gem arrives from Enroth fresh from the Succession Wars. She first helps the Clovergreen Militia and then aids a wizard's apprentice against the Necromancers of Deyja. (campaign description, taken from the game itself)

Clearing the Border

 * Win condition: Defeat all enemies (only one in this case).
 * Loss condition: Gem is defeated in combat

After the Amulet

 * Win condition: Acquire the Amulet of the Undertaker.
 * Loss condition: Either Gem, or Clancy is defeated in battle.

Retrieving the Cowl

 * Win condition: Bring Vampire's Cowl to the town of Leafhall.
 * Loss condition: Either Gem, or Clancy is defeated in combat; lose Vampire's Cowl.

Driving for the Boots

 * Win condition: Bring Dead Man's Boots to Gem's starting town.
 * Loss condition: Either Gem, or Clancy is defeated in battle; lose Dead Man's Boots.