It started as a fun day at a San Francisco park for little Senna Matkovic with his nanny and twin brother, Antun.
But moments later, the 10-month-old was on death's door. The little boy had somehow been exposed to fentanyl at San Francisco's Moscone Park.
Thankfully the fast actions by the nanny and quick-arriving paramedics pulled Senna out of danger.
This week, his parents -- Ivan and Kerina Matkovic -- and little Senna visited the paramedics at a San Francisco firehouse to thank them.
"We're just super thankful that they knew what to do in that moment," Ivan Matkovic said.
When Ivan raced to the park that day, he couldn't believe the horror of watching his son struggle for his life.
"By the time I arrived, he was laying flat on his back," he told KPIX. "They had a breathing apparatus on his face. Apparently, he was completely blue."