Kammala wannan jumlar: A shekara ta 1658, tare da rundunar manoma daga Helsingør, sau biyu ya shiga cikin kare Copenhagen. Ya ƙi yin alkawarin aminci ga Carl Gustav bayan sojojin Sweden sun mamaye Kronborg kuma an ɗaure shi na ɗan lokaci amma ya fita. Tare da matarsa, ya fara safarar kayayyaki zuwa Copenhagen wanda sojojin Sweden ke kewaye da su. A watan Oktoba 1658, ya sanar da Frederick III game da isowar rundunar jiragen ruwa na Obdam zuwa Øresund kuma ya fara aiki a matsayin mai aikawa tsakanin Obdam da Christoffer Gabel a Copenhagen. A watan Fabrairun 1659, ya gargadi gwamnati a Copenhagen game da shirin Sweden na wani
kai hari a kan birnin da kuma bayar da shi da cikakken bayani game da shirye-shirye da kuma kwanakin. Daga baya a wannan bazara, tare da Lorens Tuxen da Henrik Gerner, ya kasance babban mutum a cikin shirye-shiryen dawo da ikon Kronborg. A cikin gandun daji a Krogerup, ya shirya ganawa tsakanin bawan sarki Corfitz Trolle da Kanar Burtaniya Kanar Hutchinson wanda ya goyi bayan shirin. Ya kuma kawo Trolle cikin hulɗa tare da Oluf van Steenwinckel kuma daga baya ya ɓoye shi zuwa Kronborg. Ya karbi karamin sojojin Denmark a Krogerup kuma ya sanya shi tare da abokai a Helsingør. Ya kawo wa Hutchinson da Steenwinkel kuɗin da suke buƙata (1,200 rigsdaler na Danish gaba ɗaya) don halartar su kuma ya raka ɗan Hutchinson zuwa Copenhagen a matsayin tabbacin amincinsa. Lokacin da aka bayyana shirin a watan Yunin 1659 kuma aka kama da yawa daga cikin wadanda ke da hannu, Rostgaard ya yi kamar ya mutu kuma ya yi nasarar tserewa zuwa Copenhagen inda ya shiga cikin ƙasa na watanni 11 masu zuwa don kare matarsa a Helsingør.