Thor's Hammer was stolen by Thrym. Thrym wanted to marry Freya for the hammer back. She didn't want to marry him so Thor dressed up as her and when the hammer was given back Thor took and killed Thrym and all the other giants.
Baldor's mother, Frigg, asked everything to never hurt of kill Baldor. She accidently forgot mistletoe and Loki tricked Hod into shooting an arrow of mistletoe at Baldor. Baldor died and Loki got shut in a cave with venom dripping on his head for eternity.
Freya had a beautiful necklace. Loki stole it and turned into a seal to hide it. Heimdall saw him and turned into a seal to fight Loki for the necklace. Heimdall won the battle and gave the necklace back to Freya.