He joined the Nazi party on 1 December 1931, and the SS in October 1934, with the membership number 270620.

On 20 November 1939 he began active service and was assigned to Sachsenhausen concentration camp where he stayed until the end of June 1940.

[5] On demand, a group of prisoners were expected to undertake any action, such as walking, singing, running, crawling on one's elbows and tips of the toes, roll around on the ground covered with gravel and crushed bricks, etc.

[5] Plagge was a specialist in the invention of these exercises, which were to be performed very quickly without any regard to the age and health of the prisoners.

Hoping his life would be spared, he told the court that after atonement for his crimes, he will be regarded as a good man, but was sentenced to death due to the overwhelming evidence against him.