Grissom and Nick investigate the death of a book restorer while Catherine and Sara are called to the scene of a fatal train crash.

When the female book restorer is found dead and locked inside a "cage," a temperature-controlled workspace, Grissom and Nick attempt to determine whether this is a case of suicide or homicide. They discover that the key to solving the case may be a co-worker who suffers from autism.

Meanwhile, Catherine and Sara are sent to comb through the wreckage of a collision between a train and an SUV and find out if it is a case of road rage or simply an accident.