This story forms the fifth in a five-story arc (all set pre-Mirror Image) in which the events surrounding the staff at the Project follow on from one story to another. In case you have not read the first four, which can be found at this site - this is what has been happening.
Previously on Quantum Leap…
As Sam continues to Leap through time, Al has some past mistakes of his own to deal with, and the Personnel at the Project undergoes a major change.
The first story, Terror Firma, has Sam leaping into David Beckett, a computer genius, who helps to foil a designer drug manufacturing setup. Unwittingly, David becomes a marked man as one of the bad guys swears revenge for the (accidental) death of his twin brother.
While Sam helps a young hopeful gain a place on the Olympic Ski team in High Hopes Al learns that his third ex-wife Ruthie has been seriously injured when an anti-Semitic group blows up the train she is on. Sam persuades Al that he should visit her in hospital, which stirs up more than old memories. Tina is jealous of Ruthie's influence over Al.
In the third story, Run for their Lives, Sam becomes an Irish Nanny who must save his two charges from a pair of evil kidnappers. Meanwhile, the same faction that bombed Ruthie's train now hijacks Gushie and straps a bomb to his chest. Corporal Ralph 'Rusty' Kincaid diffuses it, but in doing so becomes exposed to the mercury used in the bomb's mechanism. Both men suffer varying degrees of temporary insanity from the mercury poisoning, but in Rusty's case it leads to him attacking Ziggy with an ax. Gushie gives his life to protect her. David Beckett, the leapee from Terror Firma is brought in to replace Gushie, and give him protection from the vengeful brother. Ziggy resents him and is less than co-operative.
Story Four, Snake in the Grass, sees Sam forced to unspeakable acts as a member of a teenage Japanese gang in San Francisco. Al remains caught between his feelings for Tina and an awkward relationship with Ruthie. Sammi-Jo discovers that Sam is her father, loses her mother Abigail to a burglar, and relives a horrific nightmare from her college days. Dr Cassandra Koulianos joins the Project Infirmary, bringing a unique skill of her own.