Fushigi Yuugi is one of my all-time favorite anime series. It's a combination of great art, music, and drama. Zap! I'm drawn to it, and once I start watching, I can't stop! (It reminds me of the bug that was drawn to the zapper in that funny scene from A Bug's Life.)
The episode you're about to watch tonight is one of the most emotional ones. Suboshi mistakenly believes that Miaka and her gang killed his twin brother Amiboshi, and does something to avenge his brother's death. That event changes Tamahome's life forever. I would say it's like a turning point for him. Because of what happens, he is forced to grow up overnight, and he becomes more mature and extremely strong (and resembles Dragon Ball Z characters). The most significant outcome is that protecting Miaka becomes more important to him than ever. Wow, what a guy, huh? So don't miss it!
Here's some information about the four gods in the story.