Heat 1 tablespoon of olive oil in a large pan over medium-high heat. Season the scallops with salt and pepper, then add them to the pan. Cook scallops for 2 minutes per side or until browned. Remove the scallops from the pan.
Season the shrimp with salt and pepper and add them to the pan. Cook for 3 minutes per side or until shrimp is opaque. Remove from heat.
Meanwhile, cook the linguine in a large pot of salted water according to package directions. Drain the pasta and reserve 3/4 cup of cooking liquid.
Back to the pan. Pour 2 remaining tablespoons of olive oil to the pan. Now, add garlic and cook for about a minute. Add two cups of your favorite marinara or red sauce and the reserved pasta water to the pan, add salt and pepper and red pepper flakes and heat thoroughly.
Once the sauce is simmering, add mussels and cook for about 4-5 minutes or until the shellfish has opened. Close the pan with a lid to speed up the shellfish opening.
Remove lid, discard any shells that did not open.
Add shrimp and scallops back to the pan and cook for another 3 minutes or so. Add linguine and toss everything to coat with the sauce.
Sprinkle with fresh basil and serve.