When a government scientist goes missing, Abby is recruited to carry on his work, but the team worries that she may meet the same fate as her predecessor.
Source: CBS
Episode Info
Episode number: 6x21 Production Number: 621 Airdate: Tuesday April 07th, 2009
When the sick marine is playing chess, he moves a pawn from column 7 forward, when the shot changes, he is moving the pawn in column 8 and the pawn in column 7 is back where it was.