After Worf is paralyzed in an accident, Dr. Crusher sends for neuro-geneticist Dr. Toby Russell, who recommends a highly radical, extremely risky, experimental surgery — against Dr. Crusher's orders. Worf must choose between the untested surgery and the traditional Klingon way: ritual suicide.

Caroline Kava (Dr. Toby Russell)
Brian Bonsall (Alexander Rozhenko)
Patti Yasutake (Nurse Alyssa Ogawa)

• Dr. Russell's surgical procedure is called Genotronic Replication. Worf recovers due to his redundant systems, but Dr. Crusher can not forgive the way that Dr. Russell practices medicine — using people as guinea pigs to test her ideas.
  
• Klingons have many redundant systems: 23 ribs, an 8-chamber heart, two livers, and a backup synaptic system. The Klingons call this concept brak'lul. We also see that the ridges on Klingon foreheads extend all the way down their backs.
  
• The Enterprise responds to a distress call from the U.S.S. Denver (NCC-54927, Yorkshire-class) after it hits a gravitic mine leftover from the Cardassian war. The ship was carrying 500 colonists. Triage was set up in all Enterprise cargo bays. When Dr. Russell uses one of her experimental drugs on a patient without trying conventional, proven treatments and he dies. Russell justifies the death in that she was able to obtain valuable data to help improve her drug. Crusher is appalled and immediately relieves her of duty, until Picard insists that she allow Russell to operate on Worf.
  
• Worf asks Deanna if she would take care of Alexander if he dies, rather than his foster parents. She would be honored to care for Alexander.
  
• The Klingon hegh'bat suicide ritual involves the eldest son handing the dying Klingon a knife (typically a kut'luch); the dying Klingon then plunges the knife into his heart; after he is dead, the son removes the knife and wipes the blood on his sleeve. Worf asks Riker to perform the hegh'bat, but Riker insists that he ask Alexander.
  
• Dr. Russell arrives from the U.S.S. Potemkin (NCC-18253, Excelsior-class) — one of Riker's previous postings, as well as being the last starship to visit Tasha Yar's home planet of Turkana IV ("Legacy").
  
• Geordi tries out a beard in this episode.