Rambo, a 9-month-old Yorkie, is one loyal pup.

His owner, truck driver Michael Siau, didn't realize that Rambo had slipped out of his long-haul truck while he was stretching his legs at a rest stop in Hannibal, Mo., the Hannibal Courier-Post reports.

Siau got all the way to Cedar Rapids, Iowa, before he noticed that Rambo, whom he thought was asleep in the back, was missing.

Siau, who admits he was sobbing during the ordeal, figured the Missouri rest area as the only likely spot where Rambo could have escaped, but wasted two days by calling police in the wrong town.

Finally, three hours after ringing the Hannibal Animal Unit, Siau got a call that Rambo had been located -- sitting patiently at the rest stop waiting for him.

The pair were reunited on Siau's trip back through Missouri, the Courier-Post reports.