Season 2: Till Death

Sam and Dana are renewing their wedding vows in upstate New York and invite
Cat, Vincent, Tess and the others under the pretenses of providing security,
since an attempt was made on Sam’s life. This subplot gives us a bit of
background into the marriage of Sam and Agent Landon: they had a son, Adam, who
died of leukemia when he was 9 years old which is why Sam got into genetic
research
. He started submitting the kid to experimental treatments until one of
them killed him.That is sad. So they just want to use the vow renewal ceremony
as a way to honor their son and what they went through as a couple.