Two mothers will meet in London tomorrow.
Two mothers who mourn dead sons. Two teenage boys who were full of a promise when they died at the roadside - one stabbed, the other shot - twenty years, and thousands of miles apart.
Two mothers who will tell you that their boys were killed because of the colour of their skin. Two mothers still waiting for justice to be properly done.
Trayvon Martin was shot dead in Florida three months ago by a neighbourhood watch captain as he made his way home from the corner store.
His parents are coming to the United Kingdom to acknowledge and say thank you for the support they have received from the British public since their son was killed.
Among the messages of sympathy which have been sent to them is a letter from Doreen Lawrence, whose son Stephen was stabbed to death by a racist gang as he made his way home in south east London in 1993.
Mrs Lawrence will welcome Mr and Mrs Martin at the centre in Deptford - which bears her son's name and aims to provide training and education to young people from disadvantaged backgrounds.
She will then take them up to Eltham, to the bus stop where Stephen was attacked, and to the memorial which remembers his short life. What will these people have in common, apart from the dreadful knowledge of what it is like to lose a child?
They might share their experiences of criminal justice systems which failed them.
It took nineteen years to convict just two members of the gang of killing Stephen Lawrence, after an original police investigation littered with failure and incompetence.
Tracy Martin and Sybrina Fulton didn't have to wait as long to see somebody in court accused of Trayvon's murder, but only after they had seen the main suspect released without charge with a claim that he'd acted in self-defence.
They may also speak of how their boys became national figures, and household names.
About how Stephen's death forced fundamental changes in a legal system in which a police force was found to be 'institutionally racist'.
About how Trayvon's death sparked national protests, and made the President say that if he'd had a son, he would have looked like Trayvon.
And perhaps they will discuss that question which is most uncomfortable for society, both British and American. Had their boys been white, and not black, might their deaths have been investigated differently?