One day, when his parents were having a banquet, Heidrek arrived uninvited and late at night, he started a quarrel which ended in manslaughter.
Hervor secretly gave her son the sword Tyrfing as she bade him farewell, and his brother Angantyr kept him company for a while.
Soon, Heidrek arrived in Reidgotaland, entered the Gothic king Harald's service, and disposed of two rebellious jarls for him.
The goðar (heathen priests) determined that they must sacrifice the most noble young man of the kingdom to Odin in order to restore good crops.
Höfund also told Heidrek to ask King Harald that in recompense for sacrificing his own son, he should receive half the Gothic army as his own.
Then, Heidrek made a coup d'état with his half of the Gothic army, using Tyrfing to kill King Harald and his son.
She often asked to go home to visit her family, and since Heidrek remembered his father's advice, he always gladly consented.
This would turn out to be an unwise strategy, because one day he made the journey to Saxony in order to see his wife among her family.
To oppose a fourth word of advice given by his father, he told Sifka a secret and asked her to swear an oath never to tell anyone.
Heidrek's son Angantyr caught the thralls, killed them and reclaimed the magic sword, but the curse had ceased.
Tolkien, Christopher (1960) The Saga of King Heidrek the Wise: Translated from the Icelandic with Introduction, Notes and Appendices.