The Warrior on the Bridge

This is a story about the Warrior who was ordered to guard the kingdom's one and only bridge. The kingdom is surrounded by mountains so that bridge is the only way you get inside the kingdom. The mountains magically prevents flying monsters and dragon riders from flying over it which was a blessing to the kingdom. The kingdom was impregnable but one day...

The king went out on a campaign. He took everyone except the Warrior on the Bridge. The king never came back.

A lot of people and monsters came to attack the kingdom but the Warrior stood firm for years. Will he still be able to guard the bridge on his own? Or can he accept the help of others to protect his beloved kingdom?