premise: they raked and whorled through the clumps of skyscrapers , then something like a tidal wave rushed toward us and all the rest of chicagoland . we thought at first we might be safe at our height in the apartment , but when muddy water came up against three - quarters of the high - set living room windows , we ran for the stairs and the roof . the water came a just few inches from where we stood , slopping over as we hung onto railings , then began to recede . What might tell us that his narrator is discussing a fiction ?
hypothesis: The fact that he 's talking about a tidal wave in Chicago tells us he 's talking about a fiction .