On the morning of 23 March 1403, she was sent by her father, the Miller of Skalitz, to collect some nails from Martin's forge. She chatted with Martin's son Henry, and asked if she would see him at the dance that evening. Henry, despite being romantically involved with Bianca, stared after Theresa as she left, and Martin dryly commented she was a "fine lass".
Only a few minutes later, the village was attacked by a Cuman army led by Markvart von Auliz and King Sigismund of Luxembourg himself. During the attack, hundreds of citizens were butchered, including Theresa's family, and the whole village was burned to the ground.
Initially, Theresa fled with Matthew and Fritz, but they are separated. She tries to hide in a haystack, but Zbyshek pushed her towards a group of Cumans, who slaughtered everyone while she watched, then attempted to rape her. Luckily, she was saved by Henry riding a stolen horse, who distracted the Cumans, giving Theresa a chance to escape - or she manages to fight them off as Henry rides past. Devastated by the loss of her family and friends, Theresa remained in Skalitz, waiting to die, sure she had nothing to live for.
However, soon after, she stumbled across Henry, about to be killed by Runt and his cronies. With the timely intervention of Sir Robard and his Talmberg Guards, they chased the brutes away from the unconscious Henry. Theresa, as part of her Christian duty, ensured that his parents were buried before taking Henry to her uncle's mill in Rattay, where she helped nurse him back to health over several weeks, finding new purpose in her life.
She remains in Rattay with Peshek, her last remaining family, and keeps house for him - cooking and cleaning. Although he is quite gruff and distant, she views him with obvious fondness. She is also a vital source of advice and information for Henry, telling him that their friends Matthew, Fritz, Matthias and Johanka escaped the attack and fled to various towns throughout the region. She prompts him to ask the miller at Ledetchko about hiring Matthew and Fritz in A Friend In Need..., and can help Henry determine the best people for the jobs in Aquarius.
Over time, Henry begins to develop romantic feelings for Theresa, and can give her gifts and court her as part of the quest Courtship. First, the two take a walk by the river, where they laugh about the pompous nature of the local gentry.
Then, Henry invites her to dinner at the Broken Wheel Tavern, where the two enjoy a meal and dance, before they are interrupted by a drunk man who insults Henry and then attempts to assault Theresa, who fights him off. Henry intervenes and beats the man up, and Theresa tenderly attends to his wounds. The two walk back to the mill together, and after a bit of awkward small-talk on the stoop, Theresa kisses Henry firmly - much to his surprise.
Finally, Theresa invites Henry to play blind-mans bluff with her. At first Henry laughs, as its a children's game, but agrees to play with her. The two sneak off to the barn as Theresa is embarrassed at Peshek finding out she wants to play a children's game. However, a storm rolls in while they are playing, Theresa realizes the rain will ruin her laundry.
She and Henry run outside to get it, then go back to the barn to dry the clothes. She is startled by a crack of lightening, and when Henry comforts her, they kiss, before lying down on the nearby hay and making love. She leaves before Henry wakes up the next morning.
Theresa is bold and flirtatious, and seems alot more experienced in the art of love than the rather clueless Henry. She is a staunch Christian, as was to be expected of an honourable woman of that time, and incredibly brave, intelligent and strong-minded. Even the Lord Hanush advises Henry that she's one of a kind after hearing that she faced off against a group of bandits to save her, and she's evidently considered very attractive - Henry describes her as "all mouth and green eyes".
Note: gifts appear to have been turned off. It's unknown if they will be reintroduced in later updates.
The gift-giving feature seems to be buggy, as it will detect what Henry has in his inventory to give as a gift, but will not remove the item once it has been given to Theresa.
- Dagger. Theresa is slightly bemused by this gift, while a confused Henry points out that it could come in handy if she is ever attacked again. Theresa is appreciative of his concern, but isn't sure a dagger will be much help against the Cumans.
- Jewellery. Theresa is touched by this sort of gift, sure that he spent too much on it. She playfully warns him not to buy her anything else, lest she become spoilt.
- Antlers. She does not like this, and tells Henry to take it away.
- Flowers. After Klara rejects the bouquet in Next to Godliness, Henry can give it to Theresa, who seems pleased.