A/N: Bone marrow transplants weren't actually available until the nineteen fifties, but for the sake of this story's plot I'm pretending they were available much earlier.
After what they'd been through, life in England seemed like heaven on earth for Michael and Natalya. It rained a lot, but the winters were milder than those in Russia had been, and the scenery was picturesque. Best of all, for the very first time in their lives, they knew what it was like to be just ordinary people living ordinary lives, with no fear of their world being suddenly turned upside down.
Michaela grew to be a tall, graceful beauty of sixteen who strongly resembled her mother, so much so that people sometimes got them confused. At fourteen, George looked just like a younger version of his father.
One day Natalya received a very disquieting telephone call.
"My name is Valya, and I'm Vladimir Wulfert's sister," the woman said. Natalya was shocked. Why on earth would Vladimir's sister contact her after all this time?
"I'm calling because I need your help," Valya continued. "My daughter, Yulia, is desperately ill with leukemia and needs a bone marrow transplant to save her life. I know that you were married to Vladimir for a brief time, and if you and he had any children together, they are Yulia's cousins, and their bone marrow may possibly be compatible with hers."
Natalya was still too shocked to say anything. She felt sorry for Valya but didn't know how to answer her. She'd never told Michaela that there was a chance that Michael might not be her biological father. She'd never anticipated that there would be any reason for the girl to know.
"Bone marrow donation is completely safe," Valya continued. "There would be absolutely no risk at all to your child's health, and it might very well save the life of mine."
"I have a daughter who was born almost exactly nine months after Vladimir's death," Natalya finally admitted. "As I remarried less than a month after I became a widow, I've never known for sure which man is my daughter's biological father."
"There's a test she can take to determine whether her bone marrow is compatible with Yulia's," Valya told her.
"Would this test tell for sure whether or not my daughter is Yulia's cousin?"
"No," said Valya. "But two people who are closely related are much more likely to have compatible bone marrow than two unrelated people are."
"So, in other words, if Micky's bone marrow is compatible with Yulia's, that makes it highly likely, but not absolutely certain, that they're cousins."
"That's correct. Please, Natalya, I know it's a lot to ask, but you're my last hope. None of the other family members are compatible."
Natalya could think of nothing else all day. For all of Michaela's life she'd wondered which of her husbands had been the girl's biological father. Now there was a way to almost certainly learn the truth, yet every time Natalya thought about it, she felt anxious. What if Micky's bone marrow did turn out to be compatible with Yulia's? It would mean that Micky was almost certainly Vladimir's biological daughter, and Natalya wasn't at all sure that she could bear to know that.
"What is it, Tasha?" Michael asked that evening as they were relaxing together in the den. Natalya told him of the phone conversation she'd had that day with Valya.
"So, what's the problem?" Michael asked when she'd finished. "If Micky's bone marrow is compatible with this girl's, it gives her the chance to save a life."
"But can't you see?" asked Natalya. "If Micky's bone marrow is compatible with Yulia's, then that means she's almost certainly Vladimir's biological daughter."
"You know that's never made any difference to me," said Michael. "I've always loved her just as if I knew for sure that she was mine."
"I know that, and I appreciate it," Natalya said. "But I've never told Micky about it. I suppose I should have."
"I never thought it mattered," said Michael. "In my wildest dreams I never imagined something like this might come up."
"Neither did I," Natalya said. "But if we're going to ask her to be a bone marrow donor, we'll obviously have to tell her why."
"We'll tell her together," Michael offered, taking Natalya's hand and squeezing it.
As if on cue, Michaela walked into the den less than five minutes later.
"Sit down, Micky," said Michael. "There's something we need to talk to you about."