Although nothing really new happens in this episode it is much more than a filler: It gives room and time for the characters and relationships to develop and grow. They have to learn to trust each other.
While watching Derek getting dressed and ready, Meredith's voiceover about finding Prince Charming somehow becomes suspicious. Can you actually be that lucky to find him - and be happy ever after?
She realizes she does not know much about him, not even where and how he lives and she keeps on asking him questions all day about what he likes, his family situation, etc.. He tries to avoid answering her and tells her to wait and see. When a patient with increasing paralysis comes in and they cannot find a reason for it, Derek assumes it is a tumor that puts pressure on his spine, but he cannot prove it. Meredith does not trust his diagnosis, neither does she trust him to reveal more about himself. She does not "want to be the gravy", she wants it all.
After finding out that she is pregnant, Cristina gets an appointment for an abortion and does not consider keeping the baby. Her firm belief that her decision is right is shaken by a pregnant woman in her forties with a carcinoma who decides to keep her baby although that will make cancer treatment at the moment impossible. She is ready to risk the cancer to develop faster because of the pregnancy. She rather wants to give birth to the child she and her husband had so long hoped for, no matter whether that will shorten her life.
Burke is angry about Alex for telling a orthodox jewish girl that she could have a bovine instead of a unkosher porcupine heart valve (which she refused to have) without consulting him before. He never has done this surgery before and feels uncomfortable asking somebody else for advice. The sick-feeling Cristina tells him just to do that and finally, Burke gives in, even allows Alex to scrub in and - succeeds.
Izzie also has a case which involves belief. Her patient calls himself a psychic and claims to have insights into the future and into people - to "know things". Izzie and Cristina find out that he has seizures, but still - he knows things that he could not possibly have learned by observation and guessing (eg. Izzies nickname 'Cricket'). When he does not want to have an operation because he fears to lose this insight, Izzie tells him that if he really believes in his ability, it wont just go away because of a surgery he needs to survive. He gives in, he believes her - and right after the operation he gives Izzie the missing ingredient for her mother's cup-cakes she desperately has been trying to find. She did not want to call her mother to ask since she left her at the age of 18. Still, in the end, she calls her and just says: "It's 'Cricket'".
Everyone wins in this episode when opening up to their feelings and towards each other. In the last scene, Derek takes Meredith to the land he owns outside Seattle and gives her the answers to her 'small' questions: His mother's maiden-name, him having four sisters, his favourite ice-cream flavor (coffee) - and he shows her his home, a trailer. Stunned, Meredith has a look around and then just smiles and puts her hand out towards him. He trusted her enough to let her step farer into his life and she now trusts him to take her hand to move on together. Together they walk towards the trailer. Confident - and happy.
Merediths voiceover sums it all up: Try to trust each other, it may be worth it:
"It's not so important that it's happy ever after. Just that it's happy right now. See, once in a while, once in a blue moon, people will surprise you. And, once in a while, people will even take your breath away."