Who would have thought that Mac Taylor (Gary Sinise) and D.B. Russell (Ted Danson) were friends?Well, they are both on "CSIs."In tonight's episode of CSI: Crime Scene Investigation (9 p.m., CBS/Ch. 2), Mac (from "CSI: NY") shows up in Las Vegas to surprise his girlfriend. But the surprise is all his when he discovers she's missing.So he asks D.B. For help.It won't surprise you to learn that this story won't be wrapped up until Friday's episode of "CSI: NY," will it?Elsewhere on TV ...The Middle (7 p.m., ABC/Ch. 4): Axl might not get an athletic scholarship after all.Whitney (7 p.m., NBC/Ch. 5): Alex lies to Whitney in order to get some time alone.American Idol (7 p.m. Fox/Ch. 13): Hollywood Week begins..Arrow (7 p.m., CW/Ch. 30): An criminal mastermind plots to take down Arrow.NBA (7 p.m., NBATV and ROOT): Milwaukee Bucks at Utah JazzThe Neighbors (7:30 p.m., ABC/Ch. 4): Debbie gives Reggie some bad relationship advice.Guys with Kids (7:30 p.m., NBC/Ch. 5): Chris is jealous of Erhie's new nanny.Criminal Minds (8 p.m., CBS/Ch. 2): An author's daughter goes missing.Modern Family (8 p.m., ABC/Ch. 4): Gloria and Alex go to a psychic.Law & Order: SVU (8 p.m., NBC/Ch. 5): The team partners with the FBI on a 25-year-old rape/murder case.Nova (8 p.m., PBS/Ch. 7): Scientists and engineers build and test two replicas of Egyptian royal chariots.Supernatural (8 p.m., CW/Ch. 30): A rabbi spontaneously combusts.Men's college basketball (8 p.m., P12N): Utah at Oregon StateSuburgatory (8:30 p.m., ABC/Ch. 4): Turns out part of Dallas' property is in East Chatswin, which gets her kicked out of the country club and Dahlia kicked out of school.Nashville (9 p.m., ABC/Ch. 4): Rayna is none too happy about Deacon joining Juliette's band.Chicago Fire (9 p.m., NBC/Ch. 5): Casey faces family issues.The Americans (11 p.m., FX): Philip and Elizabeth are ordered to plant a bug in Defense Secretary Caspar Weinberger's office.Hot In Cleveland (11 p.m., TV Land): Mamie confronts Elka about her bossines.Necessary Roughness (11 p.m., USA): Dani tries to teach a hot-headed football coach to keep cool.Happily Divorced (11:30 p.m., TV Land): Fran saves her neighbor's life.