Boil pasta according to package directions, until al dente, drain and set aside.
Add olive oil and garlic to a large skillet and cook over medium-low heat for about 1 minute, or until fragrant.
Add shrimp and spinach and cook for 3-5 minutes, until shrimp is pink and spinach is wilted. Stir in marinara and cooked noodles, toss to combine. Increase heat to medium and cook for 1-2 minutes, until heated through.