In “9 months B.C.”, Mary is visited by an angel telling her she will bear the Messiah. A mouse named Abby overhears and tells the other animals as a star begins glowing brightly in the night.
Six months later, a young donkey is tired of milling wheat and wishes to join a traveling caravan so that he may feel important. His father helps him escape the miller who owns them and he ends up with an injured ankle at the house of Mary and Joseph who just had their wedding dinner. Mary takes the donkey in and names him Boaz, Bo for short, and reveals to Joseph that she is pregnant, with Joseph accepting Mary’s situation after praying to God. During this time, Bo and his dove friend Dave, plot to escape despite Mary’s kindness, but end up staying three more months.
Meanwhile, the three wise men and their camels, Felix, Cyrus and Deborah, arrive at the home of King Herod. The wise men reveal their gifts of gold, frankincense and myrrh, but when they reveal that it is for the “new King”, he sends them on their way to meet him, but secretly sends his head soldier and his two dogs, Thaddeus and Rufus, to find and kill the new King.
As Mary and Joseph leave Nazareth in order to head to Bethlehem, Bo and Dave try another escape, but are confronted by Thaddeus and Rufus, who knew of the home by interrogating Abby. After learning that Mary and Joseph are not home, the soldier and his dogs leave to look for them. Feeling guilty, Bo decides to warn them with Dave joining him. Along the way they meet a friendly sheep named Ruth who left her flock when she saw the star but the others refused to follow her. They catch up to Mary and Joseph in time to warn them, and hide them in a market place where the soldier ties up his dogs. Bo releases the cart Mary and Joseph were using to roll down and cause a chain reaction that knocks the soldier down a well. However, he creates severe damage to the market in the process, and Joseph instead berates Bo as he was unaware of the danger.
Upset with the current outcome, Bo leaves and Dave follows until they arrive at the caravan. While happy to have found it, Bo realizes that he liked being with Mary and tells Dave that he wants to go back. Dave admits that he isn’t upset and that he just wants Bo to be happy with his decision, and the two return and make up with Ruth. They convince a frustrated Joseph to talk to Mary, who admits that it has been difficult for her and that she is scared of the importance of the baby. Joseph and Mary make up when the latter begins having contractions. They arrive at Bethlehem where Joseph can’t find an inn for Mary. The miller, who just so happened to be there too, kidnaps Bo with Dave and Ruth leaving to rescue him. The wise men arrive as well, but the camels, who are aware of Herod’s plot, are left tied to a post.
Bo ends up in a barn where he meets a horse named Leah, a cow named Edith, and a goat named Zach. They reveal that they haven’t been able to sleep because the star’s bright light has been shining through on their manger. Realizing that this is where the baby is supposed to be, the animals help Bo escape and he catches up with Dave and Ruth while spotting the soldier and his dogs. Bo finds Mary and Joseph and gets them back to the manger while Dave runs into Cyrus, Felix and Deborah and helps them escape. Ruth finds her flock and tries to convince them to follow her, but gets unexpected help from the angel who informs the shepherds and the sheep that the Savior is coming. Bo manages to fight off Thaddeus and Rufus, but is outdone by the soldier. Suddenly, Ruth and her flock, the camels and Dave arrive and dispatch with them(?) by having them hang from a cliff. The soldier lets his dogs fall, but they are saved by Bo and the soldier himself falls to his death.
All of the animals (who are now joined by Abby and assume the danger to be ongoing), shepherds, and three wise men arrive to see baby Jesus, and Bo realises that he has been carrying the new King the whole time. Deborah predicts that this event will be remembered around the world for years to come.
During the credits, it is shown that Joseph buys Bo from the miller, and Bo helps him and Mary raise Jesus . Their flight into Egypt is also shown. It is also revealed that Bo’s father has escaped from the miller and is possibly looking for Bo.