The film tells about the results of studies of Halley's comet in 1984-1986. two Soviet interplanetary stations "Vega-1" and "Vega-2" and spacecraft: the West European "Giotto" and two Japanese satellites. 1st part. A computer diagram of the Solar System and the motion trajectory of Halley's comet. Building, offices of the Space Research Institute. Soviet and foreign specialists use computers to process information obtained during the experiment. Meeting of Soviet and foreign experts. Portrait of the English astronomer and geophysicist E. Galley. An engraving depicting Halley's comet. Comet nucleus model. Astronomer at the telescope. Flight control center. Operators in the center hall at the monitors. Halley's comet in the starry sky, on the monitor screen. Flight leaders Soviet scientists V.M.Kovtunenko, R.Z.Sagdeev, V.L.Barsukov on the monitor screen. Launch of the Proton rocket. 2nd part. Soviet and foreign specialists use computers to process information obtained during the experiment. "Vega" in flight. Launch of a Japanese satellite. Spacecraft "Giotto" in flight. Computer flight scheme of the interplanetary stations "Vega-1" and "Vega-2", Japanese satellites, spacecraft "Giotto". Halley's comet model.