The premise is that much like goldfish who forget everything after several seconds, people in love are the same. They fall in love, fall out of love, feel great angst, and forget and do it all again with the promise that this time it will be different!
I believe this movie takes place in Ireland. There is a smarmy professor who doesn't want to date anyone over 30, and likes to play the field with his students. He gives them all the same book of German poetry and wants them to whisper German in his ear.
I can't really talk more about the plot without giving things away. But I definitely enjoyed this film, and would recommend it for a couple hours of interesting discourse on romance.