In a small town, a family is faced with a formidable challenge as they strive to protect their extraordinary canine companion, Semper Fi. The father, a decorated captain serving in the US Marines, and his dedicated wife, who manages their household, find themselves confronted not only with the typical challenges of raising their 15-year-old twins, but also with the mischievous adventures of their clever six-year-old daughter. Life carries on as usual for this family, until an unexpected event turns their world upside down...