We love those disheveled but indomitable women of the television world, from Holly Hunter in “Broadcast News” to Mary Tyler Moore in her iconic 1970’s television series, Tina Fey in “30 Rock,” and Michelle Pfeiffer in the under-appreciated “I Could Never Be Your Woman.” Part Hermione Granger, part Cinderella, these are the girls whose hands were always raised in class turned women who inspire us with their determination, smarts, and skill. As Joan Cusack’s character says to Hunter’s, “Except for socially, you’re my role model.” On the outside, they may appear frazzled in a just-take-off-the-glasses-and-comb-the-hair-and-she’s-a-knockout mode. On the inside, they are super-capable, super-talented, and super-lonely. Hunter’s character scheduled crying time for herself each morning before spending the rest of the day keeping everyone on track and ahead of the competition.

And now there’s Becky (Rachel McAdams), dedicated, ambitious, addicted to her Blackberry — and about to be let go. When she’s called into a meeting with the boss, her colleagues are so sure it’s about a big promotion they have congratulatory t-shirts made. On the contrary. They love her, but in these days of tight budgets, they have other priorities. Becky’s mom (Patti D’Arbanville) is not encouraging. But Becky does not give up and soon she finds herself producing a network morning show (the good news) that is so awful half its viewers are “people who’ve lost their remotes” (the bad news). They cover stories like “Eight things you didn’t know you could do with potatoes” and chirpy interviews with celebrities.

Becky doesn’t get a very warm welcome. Co-host Colleen Peck (Diane Keaton) greets her with “Enjoy the pain, Gidget.” The security guard tells her not to unpack. She has no budget. But she has an idea — the station has a contract with a legendary newsman named Mike Pomeroy (Harrison Ford playing a character somewhere between Walter Cronkite and Wolf Blitzer) who is currently being paid but not doing anything. She coerces him into sharing hosting duties with Colleen, and starts to shake things up.

Director Roger Michell shows the same gift for endearing light romance that he did in “Notting Hill.” Once again he has some sly, understated pokes at the media and some surprising cameos and clever lines. Ford and Keaton are pros who make their characters real and interesting and very funny. Patrick Wilson makes a sympathetic Prince Charming. But in every way the heart of the story is McAdams, who is a wonder, lit from within and utterly captivating.