MANCHESTER, Mo. (KSDK) - It's a message firefighters say over and over. Working smoke detectors save lives. Firefighters say that message proved to be true for one West County family when a fire started in their basement overnight.

In the middle of the night, upstairs in his home on Posthorn Drive, John Ratcliffe and his wife were asleep. His 91-year-old mother-in-law was in a bedroom next to theirs. Their son, their son's girlfriend, and the family dog, Bailey, were in the basement.

"I guess it started in the basement because I went down and saw the flames and said 'we've got to go,'" Ratcliffe said.

At around 2:30 a.m., several agencies responded, including West County EMS & Fire, Metro West, Monarch, Fenton, Valley Park, Fenton, and Kirkwood Fire. They battled flames and thick smoke.

The West County EMS and Fire fire marshal says their home had working smoke detectors and that's what saved their lives.

"Only thing we could do is get low and crawl out of there," Ratcliffe said.

Ratcliffe's mother-in-law fell on her way out of the front door.

"Hit her head and hit her arm but she didn't realize at the time her arm was burned," Courtney Brockes, Ratcliffe's niece, said.

She was treated at the hospital. Ratcliffe's wife, son, and son's girlfriend, were also treated at the hospital for smoke inhalation. All five people survived. The family dog, however, did not.

"She was a puppy," Brockes said. "The golden doodle, Bailey."

West County EMS and Fire says the home could be a total loss. Family members say they're grateful for first responders' help during such a difficult time.

"Oh my God, they were wonderful," Ratcliffe said.

"They were so great," Brockes said. "We wanted the dog. When we first got here, we wanted to make sure that the dog wasn't still in the house, that they could get the dog, and they did. They put Bailey in the garage for them so that they could bury the dog later."

The cause of the fire is under investigation.