at one point fell into a romantic relationship with a monster, something explicitly forbidden by Master Ministry rules (in addition to haphazard possession of a Star Eater [which translates to you're losing control and the SE is taking over]). Basically all witches must be indoctrinated within the Master Ministry so that their actions/magic/etc. may be monitored and regulated. Hala and her monster partner joined a quilt coven (made outside regulations, have their own rules they follow and are generally much more accepting of those who fall outside of Ministry law), but eventually they were all busted and tattled on. Samar, dealing is laws n shit, caught wind of the situation and took over herself.
Hala's partner was seized, she has no idea what happened to them. Samar did her best to provide her sister with a gentler punishment, basically meaning Hala being confined under Samar's watchful eye and lectures. Hala has more magical power than Samar, but is not as precise with wielding it (as the majority of their comparative relationship has gone; Hala is the younger reckless sister whereas Samar is the measured older sister). Eventually Hala's sentence was over (went from imprisonment to supervised reintroduction to parole to basically just promising to be a good girl serving society [fat fucking chance]).
This is what made the royal family escape and leave Ingrid and the rest of the castle's servants to fend for themselves despite definitely being able to help. Hala was coming for Samar without knowing her sister had been gone for a while; she was just going off of grapevine info of her sibling's whereabouts