The DnD 5E New Player Tutorial Adventure!

From the introduction: As you travel southward on the road, hands saluting the landscape as you hunt for Prince Generic, you come to a river. It tumbles along briskly from east to west. It's unclear how deep the water is, but it's a good twenty feet to the other side. Straddling the river is a bridge, in front of which sits an extremely bored-looking guard. A shimmering blue aura covers the air around the guard and the entrance to the bridge.