Howard, Raj, and Leonard are visiting Penny while she works at the Cheesecake Factory. The new couple, made up of Sheldon and Amy arrive, which Penny promptly refers to as "Shamy." A very honest, direct conversation ensues.
Joan believes that a sword lying in a field is a sign, and The Conscience contends that it wasn't a sign; it was just a sword in a field. The Conscience explains several ways that a sword may have found itself in a field to illustrate to Joan that she filtered out all other possibilities in order to support her beliefs.
Sol tells Max that the world cannot be easily solved with math, but Max disagrees. Sol then tells Max about his obsession and how his mind filters out everything else in order to find that which he is obsessed about. Sol gives the example of finding the number 216.