S.T.A.R Labs security guards have it rough but not because of the dangers involved with the job but the person they have to work for. Ruth Werneke is the Labs chief administrator and she is no joke. She threatened one guard with the sack because she thought he was being lazy and she moans at Tina for not finishing a report. As Tina has to stay late to finish the report she cannot join Barry at the race track. Ruth’s favourite guard notices something strange on one of the security cameras, a cool storage unit’s door opening by itself. He goes to investigate but he is injected by a syringe and dies. It appears that there is an invisible man on the loose. He releases a toxin in the lab and promptly makes his exit. Outside the lab the invisible man becomes visible (he has a device on his belt which makes this possible) and he talks about taking revenge on the city and that he will become the destroyer of worlds, which sounds lovely. Tina is startled by the labs toxi alarm. The lab goes into lockdown and both Tina and Ruth are trapped inside with the neurotoxin.
Barry calls the lab but gets an automated message saying that the phone line is currently inoperable. The Flash runs off to the lab to see what the problem is. Tina and Ruth discover the dead guard. Tina notices an empty vial holder with project pandora printed on it. Tina asks Ruth what experiments were going on in there but Ruth claims she doesn’t know. I think someone is lying.
As Barry can’t gain access to the lab he breaks into a nearby S.T.A.R Labs van which has equipment inside allowing him to contact Tina. Despite Ruth’s objections Tina shows Barry camera footage of the guard dying and vials floating across the room by themselves. Thanks to one of her retrieval programs Tina brings up the project pandora file. We find out it was a project for the government weapons research centre to develop nerve toxins. The project director was Dr Emil Velinski and the project coordinator was……Ruth Werneke. Tina admonishes Ruth for dealing with nerve toxins. Barry goes to find Dr Velinski to gain more info on the project. Barry was too late as the invisible man got to Valinski first and strangled him to death.
Meanwhile Tina was able to find out more info on the project. Two of the vials were an experimental deadly toxin. The third was the only existing vial of anti toxin. Due to the toxin being released in the lab Tina and Ruth have less than 4 hours to live.
Federal agent Quinn arrives and tells Barry to leave as he and his team will deal with the situation. Barry won’t leave but he is ordered by Lieutenant Garfield to stand down. Tina wants to analyse the toxin to find out what makes it tick. Julio jams Quinn’s radio signal so he doesn’t notice Barry talking to Tina over the police communications network. Quinn informs Tina that Barry Allen is off the case but just as he says that he is cut off (Cheers Julio) and Barry appears on her monitor. Tina has discovered the name of Valinski’s lab assistant a Dr Cartwright. Barry deduces that Cartwright will be the invisible man’s next target so he runs off to find him.
Barry brings Cartwright to the police lab so he can try to reconstruct the anti toxin. Tina tells Barry to find the vials of toxin before the whole city is infected. Quinn and his team burst in to the police lab and arrest Barry for interfering with their investigation. They also take Cartwright away to work for them. Bellows and Murphy see Barry being arrested so they go to tell Garfield. As this is happening their police car is stolen by the invisible man.
Quinn interrogates Cartwright over the project. Cartwright knows nothing and just wants to make an antidote. Quinn doesn’t seem to care if Tina and Ruth die or not. The agent looking after Cartwright is knocked out. A voice tells Cartwright that he is death and he stabs him. Barry vibrates out of his handcuffs and runs over to the dying Cartwright. Cartwright recognised the voice and tells Barry a name, Gideon (no not that one). Barry now dressed as The Flash is attacked by Gideon but he manages to shake him off. Gideon lands on a police car and has now become visible. Quinn and his team see Gideon but he disappears before they can get him.
Back at the police lab Barry and Julio find out some info on Gideon. He was a physicist and Biochemist that worked for S.T.A.R Labs 6 months ago and before that he worked for the Government Weapons Research Centre. But Gideon left for some reason. Barry goes to find him. At Gideon’s hideout he talks about poisoning the water supply so that the toxin can spread throughout the city. The Flash arrives and tries to convince Gideon to give him the antidote. Gideon tells The Flash a story of how 2,000 people died on the island of Costa Luca due to a nerve gas leak from a secret government lab developing chemical weapons. Quinn was in charge of that facility and Gideon quit in disgust. He went to work for S.T.A.R Labs for a fresh start but then found out they were developing the toxin for Quinn and that is why he started his quest for revenge. Gideon also informs The Flash that he got a brain tumour from the incident in Costa Luca and he is dying. The Flash nearly gets through to Gideon to give up his antidote but Quinn and his team storm Gideon’s hideout. Gideon thinks The Flash set him up so he turns invisible and escapes.
Tina is having no luck working on the antidote. So she tries to think of a way to catch Gideon. Ruth suggests they use his own body heat to see him when he is invisible. They fax their idea to Barry and he asks the search and rescue team for some of their new infrared gear. The Flash tracks Gideon to the Central City reservoir. Gideon sneaks up on him and injects him with the toxin. He takes the infrared gear and stomps on it (well that gear did a lot of good). The Flash’s metabolism quickly deals the toxin and he vibrates it out of his system. He sees a vial moving towards a metal water tank. The Flash conducts electricity from an electrical panel onto the metal water tank. This shocks Gideon and shorts out his invisibility device. Before he dies Gideon begs The Flash to make the people responsible for the incident in Costa Luca to pay.
Just as Quinn’s team blow the doors off of S.T.A.R Labs to end the lockdown The Flash runs into the lab and grabs Tina and Ruth. As his body rejected the toxin earlier his blood contains the antibodies to neutralise the toxin in Tina and Ruth thus saving them. Due to his involvement with the toxin Quinn is relieved of duty and will face a full investigation in Washington. Ruth will testify against him. Barry suggests that when Tina feels better they will finally get to go to the race track.
Finally we get an episode where Tina was the main focus. Amanda Pays always delivers and she was on top form in Sight Unseen.