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The girls were born in 1963 to Barbadian parents and grew up in a small town in Wales called Havefordwest. June was born first, but it was Jennifer who developed into the stronger, more dominant one. In fact, one medical expert said it seemed like Jennifer at times “possessed” her sister. Even the girls themselves described themselves as switching selves, bouncing back and forth between being Jennifer and being June.

Their lives did not begin happily. They were the only black children in their town and the ostracism and bullying was so severe school officials allowed them to leave ahead of the other students so they could reach home in peace.

They responded by withdrawing into their own world. They stopped speaking to anyone else. They communicated only with each other in a private language only they could understand. A close study of their speech revealed it was a rapid-fire mashup of English and Barbadian slang.

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Therapists decided separating the girls might force them to reenter the world. It didn’t work. The girls were sent to separate boarding schools where they retreated into full-blown catatonia, neither speaking nor moving.

When they were reunited, they retreated to their bedroom, refusing even to come out for meals. But they used their imaginations to build a huge world in that small space. They invented complicated names and stories for their dolls. The fantasies included a certain ghoulishness, with the demise of the dolls recorded in an official notebook, each with a specific cause of death.