I wouldn't say that they wouldn't make sense at all, as she was only in two episodes before seasons 5 and seasons 6. I think Miriel will be able to follow along just fine, but she won't necessarily know details.

Miriel, you're free to read this if you'd like to know what happened with River in the two episodes you missed, if you don't want to watch said episodes. If you do want to, just ignore this spoiler. If you read on a Wiki, you might spoiler everything about her. I'm only including tidbits of her importance. I really suggest you watch the episodes, though, as they're two of the very best in the entire series.

Basically--
  • The Doctor gets a message on the psychic paper saying to meet him in the Library, with a little x for a kiss.
  • He goes there, bad things happen, etc etc.
  • An archeology/excavation team shows up, River Song being amongst them.
  • She starts getting up in his business, and she has her diary, which looks just like the TARDIS. She asks him where they are in their timeline, and he has no idea what she's talking about. At this point she realizes he has no idea who she is.
  • As the episode goes on, she keeps hinting that she knows him, and it seriously irks the crap out of him. She pulls out a sonic screwdriver, and he asks where she got it. She tells him that HE gave it to her.
  • Things become dire, and he doesn't know if she can trust him. She whispers something in his ear, and he seems angry and upset, but he agrees that he can trust her.
  • More stuff happens, too much to explain. But, at the end of the episode, he's about going to sacrifice himself to save the day. She knocks him out, cuffs him, and instead sacrifices herself.
  • As he's watching her die, he begs her not to do it. She says that the last time they had met, he wept. And in a way, he always knew how her life would end. And that she knows that even though her time with him is over, his time with her is just beginning, and she wouldn't have changed anything about the time they spent together.
  • He asks her again not to do, and it's revealed that the thing she whispered in his ear was her name. He tells her that no one knows his name, and there's only one person he'd ever tell his name to.
  • River dies.
  • He has her diary, and chooses not to spoil his own future. But, the sonic screwdriver he gave her has an imprint of her soul/mind in it. He's able to upload it to the computer system of the Library, thus allowing her to live out a special form of immortality.


Basically, it is implied that River is the (SPOILER) Doctor's wife from the future, as he'd only tell someone he really loved his name. You find out that they always meet each other out of order. And even though she's died, the Doctor will see her again.