001. Immortal
They weren't immortal. They all thought they were, though, even - perhaps especially - the Three.
First as always, Kirk is killed by a damnable bridge, naturally saving the Enterprise, even if she isn't his own this around -
then Spock, also saving the Enterprise - but now from herself -
and of course McCoy, ever obstinate to his greatest friends, had the quietest death, fading in sleep back on his own home.
They weren't immortal, but for in the tales of legends.