Ahead of joining Plzen, the 20-year-old agreed a new three-year deal at Molineux.
Herc has spent the last 18 months on loan at FC DAC 1904 Dunajská Streda in Slovakia where he has been a key player in a side which qualified for consecutive Europa League campaigns.
During his time back in his home country, Herc has made 50 appearances for Dunajská Streda, scoring six times, as well as providing two of his six assists for the club in the Europa League qualifying stages.
Although yet to make a senior appearance for Wolves, the Slovakian was a prominent performer for Scott Sellars’ under-23s in the 2016/17 and 17/18 seasons prior to his move to DAC, scoring nine goals in 37 matches – including three goals in four Checkatrade Trophy ties.
Sporting director Kevin Thelwell said: "Christian had an excellent season at FC DAC 1904 Dunajská Streda and we are delighted with the progress he is making.
"The loan move to Viktoria Plzen is a good reward for his industry and will provide him with another opportunity to prove how capable he is at a high level.
"We look forward to monitoring his performances and hope he continues to make progress."
