Welcome to this beautifully expanded Gladstone Colonial, ideally situated in the 'S Section of Stony Brook and within the award winning Three Village School District. Set on a half-acre, this is a home that has been thoughtfully expanded and shows true pride of ownership at every turn. The main home features 4 generously sized bedrooms and 2.5 half baths, with solid wood floors in all the main living space and luxury vinyl flooring in the kitchen. The kitchen is a welcoming gathering space with maple cabinetry, granite countertops, and a Viking stove. One of the most special spaces in the home is the addition of the family room with vaulted ceilings, filled with natural light and complete with new glass on the sliding glass doors that allow you to enjoy the beauty of the backyard. It is the perfect place to unwind while taking in the view of the gardens and water features. Upstairs, the primary suite offers heated floors in the bathroom, while the other bedrooms have additional closets that were added for optimal storage. Adding incredible value and versatility is the legal 1 bedroom, 1 bath accessory apartment. With its own private entrance, private laundry, and beautiful finishes, it is ideal for extended family, guests, or additional income potential. The main house and the apartment each have their own cesspool, offering added convenience and separation. Major updates provide peace of mind, including architectural roofing with a transferable lifetime warranty, gas heat with COs from the conversion, central air less than a year old, a gas tankless hot water heater, 200-amp electric service, siding and gutters updated in 2021, and an 11-zone sprinkler system with drip lines to keep the grounds lush and vibrant. The backyard is truly something special. Professionally landscaped with stunning vignettes throughout. This is more than a house. It is a home that has been carefully curated, upgraded with intention, and cherished over time. A rare opportunity in one of Stony Brook's most desirable neighborhoods!