Although still relatively new, nocturnal trading in U.S. equities, defined as trading between 8:00 p.m. and 4:00 a.m., has grown rapidly. It is largely retail-driven, concentrated in a small set of securities, and marked by substantial order imbalances. Using unique transaction-level data, we show that nocturnal execution costs exceed regular-hours benchmarks but are broadly consistent with elevated adverse selection faced by liquidity suppliers. Nocturnal returns generally do not reverse during the subsequent regular-hours session, except in a small subset of high-sentiment stocks. Overall, the nocturnal session appears to be an important source of price discovery and may create profit opportunities for retail liquidity demanders despite higher transaction costs.