Don't know why, but i've only just noticed how complex the plot for Glee is...
So Finn got Quinn pregnant, except Finn's not the father, Puck is. Quinn is giving up the baby for adoption, but is actually giving it to Terri who thought she was pregnant but actually ended up have a hysterical pregnancy, and wants the baby to make Will think she was pregnant so he won't leave her, because she knows Emma has a crush on him and Will might leave her for him, but he doesn't notice her crush on him, and now she's getting married to Ken because they both don't want to be alone.
Something like that anyway. Add in a few subplots, and a song or two and you have an episode