July 17, 1975: in the silence of the vastness of space, the American spacecraft Apollo joined the orbit of the Soviet Soyuz… The airlock hatches opened and the Commander Thomas Stafford exchanged a warm handshake with his counterpart Alexey Leonov. A challenge that was symbolic, scientific, political, ideological, but first and foremost military. After six years of tricky collaboration, the Apollo Soyuz Test Project ended a twenty-year struggle for control of space. By collaborating, the two superpowers wanted at once to defuse the tensions linked to the Cold War and to reaffirm that they were the only ones to have mastered manned space flight. This documentary tells us this unique event through the testimonies of the principal mission members, specialists who bring a technical and political points of view, revealing the real stakes of the mission. Wonderful archive footage, 3D animations and now-avalaible archives of spectacular quality and rarely used will rekindle the emotion of the meeting.