Debbie and Andy are beside themselves when it emerges Sarah has a potentially devastating condition.
When mysterious bruises start appearing on Sarah's body, she's taken into hospital for tests which show there is an abnormality with her bone marrow.
She is diagnosed with Fanconi Anaemia and desperately needs a bone marrow donor.
But with no donor in sight, Debbie and Andy made a pact to do whatever it takes to save their daughter.
What they didn't expect was that that would mean sleeping together, in the hope of conceiving a saviour sibling.
Tests confirmed that their baby would be a match for Sarah, but the hope that they'd created for their daughter was at the expense of their relationships.
Alicia and Andy quickly separated, unable to resolve their differences, but Cameron and Debbie limped on determined to save their relationship.
That was until Cameron had his head turned by Chas...