Heat a grill or grill pan to medium-high. In a small bowl, combine the soy sauce, honey, five-spice powder, and ¼ teaspoon pepper for the sauce.
Season the chops with 1 teaspoon salt and ¼ teaspoon pepper. Grill for 10 minutes, turning once.
Using a brush, baste the chops with the sauce and grill until cooked through, about 2 minutes more.
Meanwhile, toss the plums and scallions in the oil. Grill the plums for 5 minutes, turning occasionally. Grill the scallions for 2 minutes.
Divide the chops among individual plates and serve with the plums and scallions. Drizzle with the extra sauce.