The two new friends take a daring quest to seek out his long-lost distant relatives.
The pair also team up with a young widow, voiced by Zoe Saldana, who has the only known map to their secret destination.
The film shows that while we may not look the same, or we may come from very different backgrounds, in the end, we're really not all that different.
"I'm grateful that films like this are being made," said Saldana. "And they're taking all the sacrifice and nobody is compromising on that."
"It is nice that you have a story line where people are celebrating that they are not alike," said Galifianakis.
"Missing Link" is produced by Laika, the Oregon-based company behind "Coraline," "ParaNorman," "The Boxtrolls" and "Kubo and the Two Strings," all of which were nominated for Academy Awards.
"I don't know what I was in most awe of, either the sets and how gorgeous and well-finished everything was, or the team behind the Laika concept," said Saldana.
"When I was lucky enough to be asked to do the movie, I saw the work they had been doing, and it is a real interesting group of people up there," said Galifianakis. "They're doing stuff that not a lot of people are doing. I don't know if anybody's doing it!"
"Missing Link" is rated PG and is in theaters now.