Valtheim Keep is a dungeon in The Elder Scrolls V: Skyrim.
There is sometimes a bandit out front of the Keep. They will demand a toll of 200 Gold to let you pass through. You can either intimidate or persuade to get passed through without paying. Otherwise, just kill them all to get through.
If this is the site for a Radiant quest, do not expect the "toll taker". Everyone here is going to be hostile and attack from the heights of the tower.
As you approach, expect at least 1 bandit to be waiting by the door. It is best to take them out quietly at range unless you are oriented toward melee combat and have good armor. Head inside the door. Look at the bookshelf across from you. There are 2 health potions for you to take. After that, look to the right. To the right of the stairs is a trapped chest. Disable the trap and grab the contents. After that, go up the stairs to the right.
At the first landing, start over to the left, toward the bridge connecting the two towers. Look toward the bridge. There is almost always a bandit patrolling it. Wait for them to start away and then sneak up and go into the upper portion of the tower. grab all the food you can and collect what alchemy ingredients you can find.
With all that collected, continue upwards. There is one more bandit at the top of the tower. Climb up there and take them down. Head back down to the bridge. Wait for the nearby guard to start their patrol back and then backstab them. Sneak across the bridge or sprint it to avoid the fire from the nearby archer.
On the far side, you will need to deal with the Bandit leader plus a few of their henchmen. Keep in mind there is likely one on the nearby bluff that will also be firing arrows in. You can avoid them by being in one of the tower buildings.
Climb up the slope and enter the far tower next to the bridge. On the first level you will find the boss chest, your reward for clearing the area. It is underneath the stairs leading upwards. It sometimes is locked (Novice level) but nothing too hard. Grab its contents. Go over to the opposite side of the room. You will find an Alchemy Lab with some Alchemy Ingredients on it: Garlic, Frost Mirriam and Elves Ears. Head up a level. Go over to the right-hand side of the bed. Look on the night stand to find the skill book The Black Arrow, V2