Surgeon Mo Effanga has decided to focus on her career, so she’s pleased when Holby boss Hanssen agrees to give her more responsibility. But Mo’s personal and professional life soon collide when her old friend Sorcia arrives with her three-year-old son William, after being in a road accident. Mo’s clearly a little uneasy around William, as he’s the child she carried for Sorcia as a surrogate. When Mo’s left to look after William briefly, they begin to bond and, when Sorcia sees, she’s certain William recognises Mo’s voice from when he was in her womb.

When Sorcia requires emergency surgery, she makes Mo promise to look after William if anything happens to her. Having helped Sorcia to have a child, Mo must now battle to help save her life. If the worst happens, Mo fears she may have made a promise she can’t keep…

Meanwhile, Cara gets emotionally involved with an elderly patient, Dora, who almost drowned. Feeling vulnerable after breaking up with her own husband, Cara decides to help Dora find the guardian angel, Matthew, who Dora believes rescued her. Raf thinks Dora’s oxygen-deprived mind is playing tricks, so he’s annoyed when he discovers Cara’s created a social media campaign, and a hoax hero turns up trying to extort money from the pensioner. It seems Raf’s skepticism is justified – but is Cara right to believe that random acts of kindness do exist?

Also, Jesse’s keen to observe the surgeon’s role with Sacha on Keller. When Guy questions his motives and capabilities, should Jesse trust his instincts or play it safe?