A friend of mine and I are learning Blue Moon Legends together. We are playing the first two basic decks.

So - he had a card yesterday with an effect that happened when he retreated. I think it was called Bethenetana or something. Can he both play that card in his turn and also retreat?

Thanks, and hope this question finds someone out there still active on these forums! Love the game, super fun (I'm a very casual MtG and Hearthstone player - nice to just buy everything in one box instead of spending hundreds of dollars over time.)

Nope, you cannot. You can play an Action card (I think that's what they are called) before retreating, but you cannot play a character. Bethenetana already has to be present from the previous turn to have any effect.