Sheldon learns the University is building a database without him. Also, Mary takes care of a bedridden Mandy and Meemaw.
Thanksgiving with Marshall's family is especially stressful for Lily because she thinks she may be pregnant. Elsewhere, Robin, Barney and Ted spend the holiday volunteering at a homeless shelter.
Hal is inadvertently responsible for a toxic chemical spill that forces a neighborhood evacuation; Malcolm deals with being grounded even in the emergency shelter; Francis suffers through a date with a geeky 12-year-old.
After Torres and Bishop are victims of a hit-and-run, Torres fights for his life in the ICU.
The NCIS team investigates an F-18 crash and the subsequent disappearance of the pilot who operated the aircraft. Also, McGee reluctantly discusses a very personal decision with his teammates.
