Each year, the team defrosted Tommy, a World War I-era soldier kept in cryogenic storage; the Torchwood members who came across him in 1918 knew he would eventually be needed to fix a time shift. They sealed instructions in a box that was keyed to open at the right time. Since joining Torchwood, Tosh placed herself in charge of Tommy, eventually growing attached to him over time. She's the one who took him on his yearly "day out" - and, before they discover that the time shift was about to occur, she slept with him. Shortly afterwards, the box opened, and Jack called Tosh to tell her to return to the Hub. He gave her her instructions, then warned her of something else - Tommy was executed for cowardice after he returned to his own timeline. Tosh was hesitant to make him return after that revelation, but she did so anyway, instructing the past Torchwood agents in what needed to be done. However, Tommy forgot about what happened in the future, so Tosh had to be psychically projected into the past to persuade him to stitch the time shift shut. Afterwards, Tosh was devastated, knowing that she'd sentenced him to death, and knowing that she had no other choice.
Sometime later, Gwen returned from a holiday with Rhys, only to discover that the rest of the team had changed to include a sixth member, Adam. He fit in so perfectly that it seemed as if he'd always been there. (The fact that he's an entity that alters others' memories in order to manipulate them may have something to do with this - he has to exist within memories in order to survive.) In fact, he established himself as Tosh's fiance, making Owen the nerdy one with the hopeless crush on Tosh. Luckily, Ianto's diary helped to reveal the true past to Jack - along with Torchwood's security footage - and Adam was captured. Jack convinced everybody to take retcon pills in order to forget Adam; they needed to find a memory that defined them and made them think of who they were. Tosh chose maths - how they're reliable and everything always works out properly. She mentioned moving into her first flat and wanting to have a flat-warming party, only to realise that she didn't have anybody she wanted to invite. All she wanted is for someone to see that she's special - taking the pill obviously make her forget the one person who did. Needless to say, they all took the pills and forgot Adam, then found a few things left behind in the Hub later. Tosh had a bouquet of flowers (sent by Owen when he was in love with her), which rather mystified her - Owen, of course, disregarded it entirely.
When terminally ill patients in Cardiff started receiving miracle cures, Martha Jones turned up to help the team investigate a facility known only as the Pharm. Owen tried to flirt with her, but she was clearly uninterested - in fact, she was engaged. Tosh commented on Martha and Owen, but Owen assured her it was going nowhere - they eventually agreed to go on a date. The team fitted Martha with contact lenses that transmitted a video feed back to the Hub. However, Martha was infected with the alien larvae, and her blood cells, mutated from traveling through time and space, allowed her to incubate the larva long past the time the previous "patients" did. Owen, Jack, and the rest of the team came to her rescue; Owen used a singularity scalpel to remove the mayfly from her stomach. Professor Copley, the man running the Pharm, threatened to shoot them as they tried to leave. While Owen tried to talk him down, Copley shot him in the chest.
Later, Martha prepared to perform Owen's autopsy, but Jack wasn't there; he was searching for the other resurrection gauntlet. He returned with the gauntlet and revived Owen - supposedly for two minutes - and the team said their final goodbyes, Tosh confessing her love for him. Owen didn't return to the dead, though, and no tests could distinguish anything. Their research eventually turned up a similar case of resurrection, when death came and took the souls of thirteen people. This time, it happened at a hospital; Owen sealed himself in with the entity of Death - briefly kissing Tosh first - and faced it down, defeating it.
Re: Toshiko Sato / Torchwood / 4 of ?
Sometime later, Gwen returned from a holiday with Rhys, only to discover that the rest of the team had changed to include a sixth member, Adam. He fit in so perfectly that it seemed as if he'd always been there. (The fact that he's an entity that alters others' memories in order to manipulate them may have something to do with this - he has to exist within memories in order to survive.) In fact, he established himself as Tosh's fiance, making Owen the nerdy one with the hopeless crush on Tosh. Luckily, Ianto's diary helped to reveal the true past to Jack - along with Torchwood's security footage - and Adam was captured. Jack convinced everybody to take retcon pills in order to forget Adam; they needed to find a memory that defined them and made them think of who they were. Tosh chose maths - how they're reliable and everything always works out properly. She mentioned moving into her first flat and wanting to have a flat-warming party, only to realise that she didn't have anybody she wanted to invite. All she wanted is for someone to see that she's special - taking the pill obviously make her forget the one person who did. Needless to say, they all took the pills and forgot Adam, then found a few things left behind in the Hub later. Tosh had a bouquet of flowers (sent by Owen when he was in love with her), which rather mystified her - Owen, of course, disregarded it entirely.
When terminally ill patients in Cardiff started receiving miracle cures, Martha Jones turned up to help the team investigate a facility known only as the Pharm. Owen tried to flirt with her, but she was clearly uninterested - in fact, she was engaged. Tosh commented on Martha and Owen, but Owen assured her it was going nowhere - they eventually agreed to go on a date. The team fitted Martha with contact lenses that transmitted a video feed back to the Hub. However, Martha was infected with the alien larvae, and her blood cells, mutated from traveling through time and space, allowed her to incubate the larva long past the time the previous "patients" did. Owen, Jack, and the rest of the team came to her rescue; Owen used a singularity scalpel to remove the mayfly from her stomach. Professor Copley, the man running the Pharm, threatened to shoot them as they tried to leave. While Owen tried to talk him down, Copley shot him in the chest.
Later, Martha prepared to perform Owen's autopsy, but Jack wasn't there; he was searching for the other resurrection gauntlet. He returned with the gauntlet and revived Owen - supposedly for two minutes - and the team said their final goodbyes, Tosh confessing her love for him. Owen didn't return to the dead, though, and no tests could distinguish anything. Their research eventually turned up a similar case of resurrection, when death came and took the souls of thirteen people. This time, it happened at a hospital; Owen sealed himself in with the entity of Death - briefly kissing Tosh first - and faced it down, defeating it.