Five-spice powder is available in Asian markets and in the international or ethnic cuisine section of many supermarkets.

1. Peel and devein the shrimp, leaving the tails on. Rinse the shrimp in cold water, drain, and pat dry. Rinse the fish, pat dry, and cut into bite-sized pieces.

2. Cook the potatoes in boiling water until they can be pierced easily with a fork but are not overly tender. Cool and cut into chunks. Blanch the asparagus spears briefly in boiling water. Drain thoroughly. Cut the spears into 1-inch pieces. Cut the celery stalks diagonally into 1-inch slices. Smash, peel, and chop the garlic clove. Chop the shallot.

3. Heat the olive oil on low heat in a fondue pot or a medium saucepan. Add the shallot and cook briefly on low heat. Add the garlic clove. Turn up the heat to medium-low and add the wine and the broth. Bring to a boil. Transfer the broth to the fondue pot if necessary; set the fondue pot on the table and set up the burner. Set the temperature high enough to keep the broth simmering throughout the meal.

4. Place the shrimp, fish, potatoes, celery, and asparagus on serving platters. Use dipping forks to spear the seafood and asparagus and dip into the hot broth. (The potatoes and celery can be dipped into the broth or eaten as is.) Serve with the mayonnaise and five-spice powder for dipping.