Litmus is the sixth episode of the 2004 TV series Battlestar Galactica and aired during the show's first season.



It is sixteen days since the Fall of the Twelve Colonies. The Scorpia Traveller lands in Galactica's hangar deck, and its occupants disembark. A Marine Corporal examines each civilian's identification. One man is cleared and begins walking through the crowded corridor which Sergeant Hadrian has also just passed. He joins a line of other civilians. Elsewhere, Deck Chief Galen Tyrol is led by Specialist Cally Henderson to an empty room to continue his relationship with Lt. Sharon Valerii, who snuck through a hatchway on C Causeway to get there a different, equally unsuspicious route. The man stops following the line of civilians and turns down a different corridor. Col. Saul Tigh takes note of the man, and nonchalantly picks up a phone, calling for Marines to meet him at the "midpoint promenade deck causeway, C level" and approach from aft. Commander William Adama also enters the causeway and takes note of the man. Following the man, he shouts out "Doral". The man turns around, revealing he is in fact a Cylon - a Number Five model - and exactly resembles Aaron Doral, the man left behind on Ragnar Anchorage. The man reveals he is wearing a suicide vest and detonates it. Commander Adama rushes to the vest, hoping to disarm it, but Col. Tigh pushes him to the floor.

Act 1Edit

On Galactica's operational sickbay in the morning, Major Cottle briefs Commander Adama on the situation. Five people are death and thirteen more are in a serious condition. The Commander and Col. Tigh are forced to reveal the existence of Humanoid Cylons to the Master-at-Arms, Sergeant Hadrian, so she can lead an investigation into how he got on the ship with explosives. Due to repeated security flaws since the Fall of the Twelve Colonies, Sergeant Hadrian insists on an independent tribunal; a free hand in interrogations outside of Command review, and public disclosure to aide in the search for any identical copies of Aaron Doral in the fleet. The Commander gives her the first two, and takes the second under advisement, alerting President Laura Roslin to it; she warns him that the situation is serious enough that someone will have to be found accountable for the security issues.

On Caprica, the Number Eight posing as Lt. Sharon Valerii watches Lt. Karl Agathon from the rooftops along with a Five and Six. He is part of an experiment to see if he is willing to stay with her after her disappearance at the restaurant. If he decides to leave her behind, he will head south to head to a space port and be shot dead by Centurions. If he heads north to known Cylon positions, it will mean he is trying to rescue her and will be allowed to escape.

Meanwhile, Chief Tyrol catches Specialists Henderson; Socinus and "Jammer" creating a distillery in the tool room. Rather than report their actions, he decides to help them perfect it. When the others return to the deck, the Master-at-Arms begins interviewing them about their whereabouts at the time of the bombing. Asking Specialist Henderson first, she says she was reading a book at the time of the bombing. Asked where Chief Tyrol was, she says she saw him on deck when she left. Jammer says he was watching a pre-recorded Pyramid game in the mess hall, and Chief Tyrol was around. Specialist Socinus says he was working on the hanger deck and Chief Tyrol arrived later to repair a Viper.

President Roslin appoints the independent tribunal, and reveals the truth about the Humanoid Cylons, revealing the photos of Aaron Doral and Leoben Conoy's body should their copies be in the fleet. The deck crew are shocked by the reveal which, until then, was only a baseless rumour spread around by Lt. Alex, though Chief Tyrol turns straight to Lt. Sharon Valerii when he hears the report. Sergeant Hadrian returns to the deck with a group of Marines, and has Lt. Valerii and Chief Tyrol brought in for questioning, much to the protest of their workfriends.

Lt. Valerii is questioned in front of the tribunal over her location - her rack, asleep. She is asked if she engaged in a relationship with Chief Tyrol against military regulations, but she insists they broke up after being ordered to. She is then asked for Chief Tyrol's location at the time of the bombing, which she does not know. Chief Tyrol is then brought in for his own line of questioning. He confirms he was on watch at the time of the bombing and reported nothing in his log. He is asked if the hatch on Causeway C was open while he was on watch; Sergeant Hadrian found it open during the investigation, which would have given quick access for the Cylon agent to separate himself from the civilian group and head to the small arms locker a Marine guard was killed by. The room however requires a passcode to enter, which would suggest an accomplice was involved. Chief Tyrol insists that the passcode is well known as many crewmembers have access to it; he deflects the line of questioning back to Sergeant Hadrian after constructing a hypothetical scenario where the Marine guard was forced to open the locker before his murder, which would become Sergeant Hadrian's responsibility. Rather than answer, Sergeant Hadrian asks if Lt. Valerii left the hatchway open, which he shouldn't know given his previous claim he was asleep in his rack. Finally, Sergeant Hadrian asks him to explain the conflicting reports given by his deck hands to his whereabouts. Refusing to answer, he attempts to exercise his right to withhold incriminating answers as per the 23rd Article of Colonization.

Back on the deck, the deckhands begin arguing over why Chief Tyrol was detained; Jammer is affected by the disclosure on Humanoid Cylons, and is willing to believe Chief Tyrol is a Cylon agent. The tribunal moves on to interrogating Specialist Socinus who was supposed to be on watch with Chief Tyrol at the time of the bombing and claimed to have seen him work on a Viper. Hearing Chief Tyrol's testimony, he changes his story to defend his senior. To explain the discrepancy, he says he left his post to smoke and eat food in the galley, and adds to his story to include going through Causeway C and leaving the door open. His attempt to defend Chief Tyrol's whereabouts makes him the fall.

On Caprica, Lt. Agathon turns south, to head to the space port but, to the surprise of the Number Eight and her Five and Six friends, decides to head north to free her. They make preparations for her "rescue". As night falls, the Five and Six take turns beating and kicking her to make it look convincing she was captured.

On Galactica's sickbay, Dr. Gaius Baltar pays Lt. Kara Thrace a visit, as she is still recovering from her broken leg. She does not care for his flirting this time, but has the opportunity to give him her theory on the Cylon bomber's motives: Dr. Baltar's secret project - rumoured to be a Cylon Detector - was on C-deck, so the bomber would have blown up his lab had he not been caught. Dr. Baltar is disturbed by the revelation and leaves the room, pursued by the Messenger Six. He doesn't understand why he is at risk of Cylon assassination if he is doing what she wants, but she reminds him that the Cylons do not know she exists. He threatens to destroy the Cylon Detector and blame it on Cylons to save his life, but is throttled by her.

Commander Adama is handed the findings of the tribunal, which is also sent to President Roslin. In a call with her, he expresses his distrust at the findings, which have found Specialist Socinus guilty of conspiracy with the Cylons to commit acts of sabotage. President Roslin is more interested in Chief Tyrol. Commander Adama is interrupted by a Marine party, who have orders to take him in for questioning as well.

On Caprica, dusk is approaching. Lt. Agathon becomes suspicious about a warehouse compound and goes into to investigate it. There he finds a Centurion dragging the unconscious Number Eight on the level below him. The Centurion turns around and approaches him from behind, knocking him over. The Centurion takes its time to arm its machine guns, but Lt. Agathon has more than enough time to destroy it. Freeing the Number Eight, he shoulders her out of the warehouse.

At the tribunal, Commander Adama is asked why he refused to go public as to the existence of Humanoid Cylons, and why he refused to inform his own security, which he explains was due to not knowing who to trust. He is asked if the bombing could have been prevented had the security team been aware of Doral being a Cylon, which he dismisses as speculation. He is asked if he believes Cylons were responsible for the water tank bombing, which he agrees. He is asked if he believes there are Cylons on the ship, which he also agrees. He is asked if he allowed Chief Tyrol and Lt. Valerii's relationship to go ahead, allowing two suspected Cylon accomplices to collude in secret. Commander Adama rejects the entire tribunal as a witch hunt and orders it to be shut down. When he tries to leave, Sergeant Hadrian orders the Corporal-of-the-Guard to restrain him for further questioning. Commander Adama likewise orders her to be confined to her quarters. The Corporal-of-the-Guard follows the Commander's order, and the tribunal is called to an end. 

President Roslin reports on the amended tribunal findings on a live wireless broadcast. She reports that the Cylon was found to have obtained explosives after making his way through the hatch on Causeway C, left open by the negligence of Specialist Socinus, who further confessed to lying under oath and dereliction of duty at a time of war and is stripped of his rank and confined to the brig. Chief Tyrol makes his way to Commander Adama's quarters, hoping he will let Specialist Socinus out by explaining he lied to protect him for his relationship with Lt. Valerii. Commander Adama is well aware Specialist Socinus is probably innocent of the charge, but it doesn't matter - Chief Tyrol's actions meant a gap in the chain of command, and Specialist Socinus' whereabouts cannot be corroborated, and he deserves to be in the brig for lying under oath. Because of Chief Tyrol's irreplaceable skills, he cannot be sent to the brig, and Commander Adama hopes he will be punished psychologically in knowing he has ruined a friend's life over it. Chief Tyrol immediately breaks up with Lt. Valerii because of the experience. Before lying, he asks if she left the hatch open, but she fails to answer.


  • Story By:
Teleplay By: Jeff Vlaming
  • Directed by: Rod Hardy

Guest starsEdit



External links Edit