Cartan and Nat met in their sophomore year at Marquette- they had a few classes together that year, but they didn't talk to each other until their Meteorology class. Nat had missed a class on Advertising Principles earlier in the week and needed notes - conveniently she noticed the cute guy that shared that class with her being called to the front of the class in Meteorology to spin the globe for the professor (to demonstrate how the sun affects the weather). She asked him for the notes after class and he asked her if she wanted to talk over lunch. They stayed friends for a whole semester and hung out pretty much everyday, quickly becoming close friends. Cartan worked up the courage to ask Nat if she wanted to be his girlfriend before boarding the Amtrak home for winter break... and the rest is history!