He used to be a memorization genius, but has failed 9th-grade civil service exam for 3 years, resulting in him unable to find other jobs and working in MS Mart owned by his mother Jung Myung Sook.
With excellent observation and extraordinary memory hidden in ordinary visuals, he began to dig into mysterious murder cases through mart receipts, revealing truths that no one could have expected, signaling the birth of a detective he had never seen.
(Source: Wikipedia; Kpopmap)
