"You are a guest of the count, one of your allies and the strongest man in the region. Your sojourn has been pleasant, a nice change after weeks of battle. Suddenly the courtyard below your window is filled with the noise of galloping horses. More guests?"
"You yawn as you look out. But these people arriving look more like tax collectors than guests. You decide to give your attention to something more interesting, like dinner."
"Relax while you can, friend, because these new arrivals are about to lead you to a crimson sailor, a cozy Tower of Terror, and a river with an aching heart."
CM3 Sabre River is a high level module with Conqueror to King level encounters we're talking table X (10) encounters. And the then there's the fact that the players can be challenged to high level wrastling matches. And there's a good chance that one or more of the party will die. And did I mention the dungeon crawls are cleverly woven into this one.
If there was ever a module that cleverly worked it's Mystara and high level end encounters it's CM3.