​​The Anthropoid, Silver and Out Distance air drops were sent from the United Kingdom and organised by the exiled Czech Government in London. They used British aircraft crew and Czech paratroopers, with the help of Resistance on the ground.

On the night of 27 to 28 March 1942, paratroopers from the Out Distance air drop landed in the Protectorate Böhmen und Mähren (modern Czechoslovakia), at that time under German occupation.. The group’s task was to guide the aircraft to their bombing targets. For this reason, the group's equipment included a Rebecca radio. Unfortunately, bad luck accompanied the landing; the radio had fallen into the hands of the Gestapo. This, of course, meant they could not contact the aircraft to guide them, and so required some improvisation to find a solution. The target area was therefore marked out using flames as signals.

​On 23 April, paratroopers already operating in Pilsen were joined by Karel Čurda, from Out Distance. They met at the Klatovský avenue apartment, where František Král, his wife Karolína and their two children lived. Their neighbours were, Aloisie Hrdlička and her son, Jiří. Both families supported and helped the paratrooper air drop groups sent from the UK. Their aim was to plan the details of the mission. The next day, the final check of the preparations took place.

​However, Čurda betrayed all his comrades, including those from Pilsen. Aloisie Hrdličková and her son, Jiří Hrdlička, were taken into custody by the Gestapo. On 24 October 1942, they were sentenced to death and murdered at the Mauthausen Concentration Camp at 10:14 and 16:00 respectively.

​František Král was not arrested until 14 August 1942. Him and his wife were sentenced to death. On 24 October 1942, Karolína Králová was executed at 10:06, and František Král at 15:52 in Mauthausen Concentration Camp. The two children were miraculously released from police custody and lived to see the end of the war.