I know some people may be interested in watching Torchwood for its ties to Doctor Who. That's fair. In fact, you may enjoy it's first two seasons for its monster of the week structure, or its third mini-season as it's legitimately good.
However, stay far FAR away from Miracle Day. The entire plot of the season is based on the mother of all plot holes that insults the intelligence of the viewer. Not to mention the writing, especially in the final episode, is god awful. For those that have suffered with me these past ten weeks, you know exactly what I'm talking about.
Here's what happened for those that don't care/don't believe just how bad it was...
Long story short, back in the first season of the new Who Captain Jack died. Then a time vortex thing flowed directly through him. He's not immortal due to changed DNA or any other special physiological trait. It's more like he must always exist as he did that day. He gets shot? Nope, he wasn't shot that day, back to normal. Hand chopped off? Nope, he had both hands that day, back to normal. Other than timey wimey nonsense, he's a normal human.
Now to Miracle Day.
Everyone knows the premise. People can no longer die, but Captain Jack can. After the first episode, the next SEVEN EPISODES are spent figuring out the Miracle is called the Blessing by the people who intentionally started it.
In the final episodes you find out there's this giant Earth vagina of nothingness going through the entire earth from Shanghai to Buenos Aries. Somehow Earth's vagina has created this "mophic field" that ties all of humanity together. Specifically, the average life span of a human.
Previously there was an entire flashback episode of Jack going to New York before WWII and having gay sex. Somehow he gets locked up in a cellar and people come to watch him die over and over. Some people collect his blood for some reason. However, it is stressed repeatedly over three or four episodes that there is literally NOTHING special about Jack's blood.
Back to Earth's vagina, these people made everyone "immortal" by dumping Jack's old collected blood into the vagina from both sides at the same time. Good guys reset things by Jack dumping his somehow now mortal blood into one side, and his friend transfused with Jack's blood dumping that into the other side. Yay, good guys win.
Also, the bad guys spent the whole season trying to kill Jack because they knew he was the only person who could reverse the Miracle. So instead of killing him dead on the spot when he was looking at the Earth vagina surrounded by guards, OR letting him commit suicide by dumping his blood into only one side of the vagina, the bad guys spend five minutes explaining how to defeat them.
Now to a funeral for a friend, previously mentioned friend transfused with Jack's blood gets assassinated by a CIA mole. EVERYONE CAN DIE NOW! OH NO! Oh, wait, turns out Jack's blood made him immortal too.
The entire story for Miracle Day is literally based on a plot hole.