The Russian dancer Sergei Polunin, born in the Soviet Union, arrived at Britain’s Royal Ballet School at 13. By 19, he was a principal dancer at the Royal Ballet, its youngest principal ever. But after two years at the Royal, he left, a peregrine falcon needing more air and vast space. Polunin wanted to control his own destiny and work free-lance. He has now teamed up with the tender and lovely Alina Cojocaru for a Romeo and Juliet choreographed by her partner Johan Kobborg. The set is a fascinating fortress of stairs, a bit de Chirico, and Kobborg has taken on the great Prokofiev score. One night only. Expect fireworks. —L.J.