The Answer is 17

ALIENS INVADED EARTH. Seventeen-year-old Addie attributed survival to their bunker until the generator failed, forcing her and Gibson, their family dog, to hike through the forest toward a safe zone. Gibson was all in at "safe" because protecting Addie is his Golden Rule. Reaching their destination, however, will be his ultimate test as her defender. When their eight-day journey begins, the odds of making it look grim. Winged aliens are lethal hunters. And other survivors are desperate for supplies. Take Sawyer. Sure, he's captivating and bold, but mostly, he's starving. He boasts he would've nabbed Addie's overstuffed backpack if it hadn't been for Gibson's counterattack or the aliens in close pursuit. Now, Addie must decide. Will their chances for survival improve by joining forces with Sawyer, even if the Olympic swimmer can't be trusted? The answer is a toss-up. One thing is clear. Wrong answers get you killed.