A plausible interpretation is that Elizabeth and Mary were linked via Elizabeth's mother rather than through Elizabeth's father. If Elizabeth's mother was from the Tribe of Judah and her father was from the Tribe of Levi, she may be referred to as an Aaron's daughter. In this case, she would have been a sister to Jesus and James, both of whom had prominent roles in Christianity.
Another possibility is that they were cousins. Both women were descendants of David and therefore sisters under the law. If Elizabeth was from the Tribe of Judah and Mary was from the Tribe of Benjamin, they would have been first cousins once removed. They would have been second cousins twice over but only the closest relatives were granted the honor of marrying their cousins.
It is also possible that Elizabeth was from the Tribe of Dan and Mary was from the Tribe of Joseph. These two tribes did not have a marriage relationship but rather a political one. However, this explanation is unlikely because Jesus was born during the time of Herod the Great who was a descendant of the Tribe of Dan. He would have been a close relative of Elizabeth.
Finally, it is possible that they were not related at all. The Bible does not explicitly say how many siblings Elizabeth and Mary had but it does mention that they had more children after John. This could mean that Elizabeth had another daughter after Mary or it could mean that there were other siblings between them.
Elizabeth was Mary's aunt, the sister of Mary's mother, Anna. Joida, the High Priest of Aaron, was the father of Elizabeth and Anna, and hence Jesus and John the Baptist's grandfather. Her spouse, Joseph, was the Virgin's first cousin. They were from the tribe of Judah.
According to the New Testament, Elizabeth "was filled with the Holy Spirit" (Luke 1:35), and she spoke these words: "And God hath made him [Jesus] mighty against the devourer... For he shall destroy the beastly devourers out of his path." She also said to Mary, her companion at the time:"Of my kinsman have I heard such things; he shall be great, and shall be called the Son of the Highest: and the Lord God will give unto him the throne of his father David." These words are quoted by some scholars to support the theory that a dual monarchy ruled over Israel and Judah during the time of Christ. However, others believe they refer to events in the future, when Jesus would defeat the Roman army and be crowned as king of Israel.
In any case, it is known that Elizabeth lived a holy life and prayed to God regularly. This is why the Holy Spirit came upon her when Mary visited her on her return from Bethlehem (see Luke 1:41).
According to the Bible, Mary and Elizabeth were cousins. While this looks to be a simple response, there is more to Mary and Elizabeth's relationship than meets the eye. In Greek, the term "cousin" is "suggenis," which meaning "kinswoman" or "related." The term "suggenis" does not always mean "cousin." For example, it can also be translated as "friend." Thus, Mary and Elizabeth were not only cousins but they were friends as well.
Cousins often help each other out in times of need. Since Mary was pregnant at a very young age and had no husband or father figure in her life, she likely needed help from someone who knew what it was like to be in her situation. God chose Elizabeth, one of His own people, to be the person who would help Mary bear Jesus' brother.
Jesus said that He loved both Mary and Elizabeth, showing that they were not just relatives but friends as well. We know today that Elizabeth died before Mary did, but we still see her name listed among those who witnessed Mary's testimony before the Sanhedrin (Mt 1:5). This shows that Elizabeth was there to support Mary even though she was not living in Palestine at the time.
Bible-based movies sometimes get some details of history wrong but they usually do a good job overall with telling a story that leads up to something significant in God's plan.