It is a prequel TV series to Thor (2009) following the adventures of Thor before he wields Mjolnir but instead wields Jarnbjorn. This Thor is around 18-19 years old. This show shows more of the Thor/Loki relationship before he turns evil. it will have a few appearances from Sif, Heimdall and the three Warriors. This is part of the Marvel Cinematic Universe (MHM15).