Nobody beats my Southern nana in making this!

2 cups of cooked white rice, preferably day-old
1/2 pound of crawfish tails, peeled and deveined
1/2 pound of shrimp, peeled and deveined
1/2 pound of Andouille sausage, sliced
2 tablespoons of vegetable oil
1 onion, finely chopped
2 cloves of garlic, minced
1 bell pepper, diced
2 stalks of celery, diced
2 tablespoons of soy sauce
1 tablespoon of Cajun seasoning
2 green onions, sliced
Salt and pepper to taste