Search Party — TBS's terrific, odd sendup of millennial foolishness that ripened into a mystery only to shift genres once more in the finale — returned Sunday for a tricky sophomore season that replaces the quarter-life crisis powering the first season with a very 2017 concept of guilt. What happens when a group of characters whose lifestyle is almost pathologically confessional have to cover something up? The series, which focused on Dory Sief (Alia Shawkat), a dissatisfied seeker who starts filling the holes in her life by searching for a missing girl named Chantal (Claire McNulty), was never easy to define.