After 2 years in space, a satellite is returned to earth and is found to have a mysterious substance on its outside surface. Tamara is called in to help in the investigation until Keith Mason and his team from Ames Research push her aside and exclude her from valuable information. Tamara has, however, reserved a sample and does her own research, enlisting D.B.'s help, and discovers that amazingly enough, the substance contains living cells. Mason finds out what she has done and takes steps to bar her completely from further involvement. For the first time Tamara begins to realize that there is more going on than she ever suspected and realizes that she will likely never find out the truth behind what she has found. Meanwhile, while preparing for his first Shuttle mission, Reggie makes the (well-intentioned) mistake of allowing a friend to sleep at his place for a few days. The distraction of a loud houseguest and the stress caused by lack of sleep have him making careless mistak

An elated Reggie Warren has finally realized his dream and has made it into space on a routine mission of a construction EVA and scientific reasearch. All does not go well for long, however, turning his dream into a nightmare. While Reggie and Japanese astronaut Hiro Furukawa are outside the orbiter on an extended EVA there is an accidental release of mercury sulphur gas during one of the experiments inside of the shuttle. On their return inside they find the 2 scientists disoriented, sweating and confused as to what has happened. Reggie must muster all of his faculties to return the Shuttle back to earth and save himself and his crew as he realizes that he too has been exposed to the toxic gas.

With many prominent politicians and military people expected, there are hectic preparations underway for the celebration at NASA to be coupled with the arrival of Space Shuttle Atlantis from its latest mission. With everything going on, the last thing that base personnel need to contend with is a bomb threat. Bull is drawn into the investigation with only a few hours to find out if there is a bomb, where it could be and to disarm it before Atlantis lands. Also, Jack and Zeke are participating in an experiment testing the design of a newer lighter space suit. Jack, in a careless moment, fails to monitor Zeke in the pressurized tank. When Zeke collapses, Jack rushes, unprotected, into harms way to rescue Zeke - only to collapse himself.

On a routine shuttle mission to launch an Italian satellite, Tamara, Dwight Ellis and Italian astronaut Mario, experience a strange flash of light - then darkness. When systems are restored they are horrified by the sight of the satellite, on the end of its severed tether, floating off into space. Although no one is quite sure what has happened, Tamara is unsettled by a vague memory from the darkness, something she chooses not to discuss. On their return the investigation turns ugly with much finger-pointing and recrimination solving nothing. Dwight, however, begins to hint that he too saw ""something"" but is also reluctant to divulge too much. Tamara presses him but, amid the wild speculation that something ""extraterrestrial"" may have been involved, he chooses to deny everything in fear of destroying his career.

With massive hurricane Elena churning in the waters off the coast, Bull, Harry Krause and Officer Del Gibons ignore the ""All-clear"" from the National Hurricane Center and continue with preparing the cape for the worst. Working into the night, Bull orders that Shuttle Atlantis be moved to safety in the Vehicle Assembly Building and assists with the evacuation of local residents. With the hurricane moving in, Riles receives an unwelcome guest. His ex, Joanna, has returned to reclaim their son, seeking to take him with her on her next assignment - and away from Jack. With the storm raging around them, Jack and Joanna argue for custody of Noah. D.B., Zeke, Peter, Reggie and Barbara are at the Moonshot, helping Sweets prepare the bar for the hurricane. Peter, disappointed that his concert plans were scrapped because of the storm, cannot believe his eyes when, at the bar sits his idol Edgar Winter! As Elana makes landfall, the pier is ripped from the shore and they realise they are all

The ASCANS are in high spirits as graduation day approaches. Unfortunately Bull receives word that NASA has plans for deep budget cuts and one of the ASCANS will have to be dropped from the program before graduating. The rather distasteful task of deciding ""who"" falls to Bull, Reggie, and Jack to decide who will not be allowed to finish the program. During an interview with the ASCANS it is revealed, by the reporter, that one of them will be removed from the program causing all to worry about who it will be. Finally the decision is made and not even a speech by their idol, Buzz Aldrin, can take away the pain of the remaining ASCANS as they remain fully aware that one of their own is unjustly missing.

To improve relations during a time of sensitive talks with the Arab Federation, NASA has (reluctantly) agreed to accept the son of King Alfazz into the space program. Although the Prince had particpated in the International Training Program 3 years prior, (and in which he placed last overall in his class) Bull and Krause are not happy with having to place him into an already prepared mission - especially when there are so many others better qualified, waiting to go. This is not a negotiable decision, they learn, and they are left with no choice but to agree with the politicians. The arrival of the Prince does nothing to make them feel any differently about the decision. The Prince is arrogant and dismissive of everyone, issuing orders and refusing to co-operate with anyone. First teacher in space, Peter is especially affected by the Princes arrival - he will lose significant amounts of time that were supposed to have been allotted to his class, to be taught around the world each d

Bull becomes the prime suspect in a series of information leaks to outside companies - especially since one of these civilian companies has approached Bull with an especially lucrative job offer. With his security access severely limited, Bull must find a way to investigate these crimes and find the real culprit, in order to clear his name and save his career. While awaiting a gold pin for his heroic work on the Atlantis mission, Zeke learns that he may instead be charged with a felony when mission patches, supposedly signed by him, are found for sale at a space convention, by Barbara. What he discovers is that his crooked brother Curt has been behind the scam and now Zeke must decide if he is able to turn his brother in to clear his own name or continue to protect him.

Bull and Andrea's relationship is put to a test when, while in Washington on business, Bull runs into his ex-wife Ellen and they share a quiet dinner together. When Andrea finds out that Bull has spent the evening with Ellen she is hurt and jealous and turns to her ex, Jeff Mason. Jeff's company is supposed to be preparing important sections for the new space station and the company is way behind schedule in its work. He has been sent to divert NASA's attention from his companies short-falls and a distracted Andrea proves to be the perfect tool to achieve this. Barbara, meanwhile has a huge problem to solve. The time capsule that was buried after the first moon landing has mysteriously disappeared. Buried next to the launchpad it was to be excavated in front of the press, during an anniversay celebration. In order to prevent a publicity nightmare for the Kennedy Space Center she must find out what happened to the time capsule and return it before the ceremony.