Sherlock becomes terminally ill and is wasting away in suffering. John takes care of him, does anything he can for him as a doctor and as a loving friend.
One day it becomes too much and maybe Sherlock is barely lucid from pain and medication. John decides to end it all, his mind perfectly clear and calm, like John Watson always is in extreme situations. He injects Sherlock with a fatal dose of something that guarantees a painful death and holds Sherlock in his arms the whole time. When it's done and Sherlock is dead, John injects himself with the same thing and dies with Sherlock in his arms.
And this is how they are found. Maybe it takes quite a bit of effort to get them separated due to the rigour mortis.
Bonus: johnlock never really happens, but when Sherlock becomes ill they do confess their feelings and regret all the time they lost.
John/Sherlock. Terminal illness. Death. Suicide. Angst.
One day it becomes too much and maybe Sherlock is barely lucid from pain and medication. John decides to end it all, his mind perfectly clear and calm, like John Watson always is in extreme situations. He injects Sherlock with a fatal dose of something that guarantees a painful death and holds Sherlock in his arms the whole time. When it's done and Sherlock is dead, John injects himself with the same thing and dies with Sherlock in his arms.
And this is how they are found. Maybe it takes quite a bit of effort to get them separated due to the rigour mortis.
Bonus: johnlock never really happens, but when Sherlock becomes ill they do confess their feelings and regret all the time they lost.