One can only die once and thus, in a closed cohort, any excess death relates to a missing death at a different point in time. This mortality displacement across age and time can be formulated as a convolution — a re-shuffling of one time series to yield another. Central to the convolution is an object of scientific and public interest: the distribution of life time lost (or gained) due to an intervention. This intervention can be a heat-wave, a pandemic, a war, or, on the positive side, an improvement in perinatal care. After introducing the convolution formulation of mortality displacement I demonstrate how to estimate the distribution of life time lost during a summer heatwave.