Kramer knew John Grossbard a while back. He got Kramer involved in some kind of shady pyramid schemes.
When Kramer lived on Third avenue and 18th street (around 1972) John Grossbard was his roommate.
But Grossbard was always behind in his rent. Then one month, he asked Kramer to loan him his share of the rent (240 dollars). The rommmate took the cash and disappears. Kramer never got the money back.
Finally, Kramer finds Grossbard at the airport and buys a ticket for Grossbard's flight. Once in the plane, Kramer goes forward and confronts Grossbard. For his part, Grossbard doesn't seem to recognise Kramer from twenty years ago (then again, he apparently had short hair at the time). After trying in vain to reach Grossbard's wallet, Kramer is escorted off the plane.
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