Read more about Margo, Moki, and Derek at: Wikipedia

Official Site: Warner Bros.

The Greatest Adventure: Stories from the Bible is a direct-to-video series produced by Hanna-Barbera that tells of three young adventurers—Derek, Margo, and 'their nomad friend' Moki—who travel back in time to watch biblical events take place first-hand.

Foreign exchange students Derek and Margo are college friends who are gaining field experience in their archaeology major by joining an excavation team. While they are with the team, a young Bedouin named Moki befriends them.

Moki, known for his hijinks and huge appetite combined with his high metabolism, is fascinated by these two (apparently) American visitors and gets heavily into pop culture through them. He wears in addition to his beaten, battered clothes a blue hat (which he was probably given by them) that has a generic white letter "D" on it. (This is possibly a Detroit Tigers cap, but the style on the letter is kept generic, possibly to avoid trademark infringement.)

The team find themselves on an excavation site, wherein which they stumble upon a trap door hidden in the sand. They fall into the trap, and end up inside of a large cavern. The opening of each video explains it this way:

Margo, Moki, and Derek has not been a contender in any CBUB matches.