Walter stays with Fauxlivia during the evening, the two having happily reconciled their past hatred from before when she had infiltrated the prime universe's Fringe team for nefarious purposes.
Walter, in recounting the Sherlock Holmes case of "The Adventure of Silver Blaze", gives Fauxlivia the idea that Broyles may be their mole because of a conspicuous lack of evidence.
Unknown to them, Broyles has been coerced by Jones into sabotaging the efforts of the Fringe division in order to maintain a supply of life-giving medication for his son, Christopher (Curtis Harris).
The Fringe team track down Broyles, and are surprised when he readily gives himself up in the bridge room, having previously contacted his prime universe counterpart to arrange his surrender.
"The Consultant" was written by DC Comics' Fringe writer Christine Lavaf, while Smallville veteran, Jeannot Szwarc, directed the episode.