In a large stockpot bring 4 gallons of water to simmer.
Add Cajun seasoning, peppercorns and hot sauce. Bring to a boil. Add the onions, lemons and garlic, and simmer around 10 minutes. Add the potatoes and andouille sausage, and simmer for about 10 minutes. Add the corn; cook for another 5 minutes.
Add the crab, shrimp and clams, bring back to a boil and cook for 5 minutes.
Add the mussels last, when everything else is almost done, and cook for another 3 minutes or until the mussels have opened. Drain quickly to stop the cooking process.
Serve with melted butter, seafood sauces and your favorite local craft beer or wine.