Ep 13. Breathe

Sherlock and Joan take on a case involving a young woman, Sophie, who is suffering from a severe case of cystic fibrosis. She is in desperate need of a lung transplant, but she and her mother refuse to take part in the transplant waiting list as they believe the system is flawed and favors wealthier patients. Sophie's mother has taken matters into her own hands and has been trying to procure a donor through other means.

As Sherlock and Joan investigate, they discover that the mother has been working with a sleazy lawyer, who has been illegally obtaining lungs from deceased patients. However, they soon realize that there may be more to the story when a patient who was thought to have died of natural causes is discovered to have had his lungs removed while he was still alive.

Meanwhile, Captain Gregson is dealing with the aftermath of a shooting that occurred at a local community center. One of the victims was a young girl who was a participant in the center's science program, and Captain Gregson takes it upon himself to visit her in the hospital. He becomes invested in the girl's recovery and tries to do everything in his power to help her.

As the investigation into the lung-transplant scheme continues, Sherlock and Joan discover a shocking connection between the illegal organ procurement and the shooting at the community center. They realize that they must work quickly to put an end to the scheme before any more lives are lost.

Throughout the episode, themes of healthcare inequality and the ethics of organ donation are explored. The characters are forced to confront their own biases and preconceptions about the healthcare system and what it means to have access to quality care. Ultimately, the episode serves as a commentary on the flaws and inequalities present in the healthcare system, and highlights the need for reform and change.