Short answers, pulled from the story.
The Crimean campaign began on the 26th of September 1941, when German and Romanian forces invaded as part of Operation Barbarossa. The subsequent German occupation lasted until the Crimean offensive of the 8th of April 1944 to the 12th of May 1944, when the 4th Ukrainian Front recaptured the peninsula.
The Siege of Sevastopol lasted 250 days, from the 30th of October 1941 to the 4th of July 1942. The city surrendered on the 4th of July 1942, though some Soviet troops held out in caves outside the city until the 9th of July.
The invading Axis force was led by Germany, with support from Romania and Italy. The German 11th Army and the Romanian Third and Fourth Armies conducted the fighting, opposed by the Soviet 51st Army and elements of the Black Sea Fleet.
On the 6th of November 1941, the Romanian submarine Delfinul, commanded by Constantin Costachescu, torpedoed and sank the Soviet cargo ship Uralets (1,975 tons) 4 miles south of Yalta. The Delfinul then evaded up to 80 Soviet depth charges by routing along the Turkish coast before reaching Constanta on the 7th of November.
The Soviet government awarded Sevastopol the title of Hero City because its defenders withstood a 250-day siege against German and Romanian forces. Multiple major Axis assaults in November and December 1941 were repulsed before the city finally fell on the 4th of July 1942.
Operation Bustard Hunt was a German military operation launched on the 8th of May 1942, targeting the city of Kerch. Soviet forces had briefly recaptured Kerch during an amphibious operation near the end of 1941; Operation Bustard Hunt retook the city for the Axis.