When she turned eleven, she started attending Hogwarts School of Witchcraft and Wizardry. Her Muggle neighbours were under the impression that she had been sent off to an exclusive all-girls boarding school in England.
At some point during her teens Isobel became romantically involved with Robert McGonagall, a Muggle who lived in the same village. However, since she knew her parents would disapprove of the relationship, she kept it a secret from them.
Deeply in love, Isobel (then aged eighteen) and Robert decided to elope, angering both sets of parents. Mr and Mrs Ross were so upset that they completely severed ties with their daughter. On the honeymoon, Isobel could not bear to tell her new husband she was a witch, and so the fact remained a secret.
The couple's first child, a daughter, arrived on 4 October. Isobel, missing her family and the magical world she left behind in the name of love, named the baby Minerva in honour of her own grandmother, a powerful witch. The residents of Caithness found this name extremely unusual and Reverend McGonagall found it very difficult to explain to the members of his congregation why Isobel had chosen it.
After Minerva's birth, Isobel became moody, alarming her husband. When Robert consulted his friends, they told him that post-partum depression was not uncommon for new mothers to go through, and that it would soon pass. However, Isobel only grew more withdrawn, sometimes hiding away with Minerva for days on end.
What Isobel was actually trying to do was keep Robert from catching sight of any of the subtle signs of being magic that Minerva had displayed from her very first hours of life. One night, she finally broke down under her husband's gentle questioning, and, in tears, retrieved her wand from where it was hidden and showed him she was a witch. Robert, while shocked by this revelation, did not love Isobel any less after it. Isobel also explained how she was bound to keep the existence of the wizarding world secret from Muggles by International Statute of Wizarding Secrecy.
While the couple still loved each other afterwards, they never regained the sense of trust they once shared, something which Minerva, a very bright, observant child, recognised.
Isobel and her husband eventually welcomed two more children: Malcolm and Robert Jnr. In time, both proved to be magical, and Minerva readily helped her mother teach them that they could not go around showing off their magical powers, and helped her cover up the accidents their magic sometimes caused.
Isobel wept when Minerva's Hogwarts acceptance letter came, not only from pride, but envy. While Minerva was closest to her father due to their similarities in temperament, she sympathised with the difficulty her mother faced. Her mother's difficulties steamed from having to blend into an all-Muggle village, and in being apart from other people like herself and having to restrain the use of her powers.
Magical abilities and skills
- Charms: Isobel had graduated top of her class in Charms at Hogwarts. This meant that she must have achieved excellent results in this subject. She was highly proficient with this branch of magic.
- Flying: Isobel played as a Quidditch Captain in her youth at Hogwarts, meaning she would have been an excellent broomstick flyer and Quidditch player.
- Pottermore (First mentioned)
- Wizarding World (Mentioned only)
- Harry Potter: Hogwarts Mystery (Mentioned only)
- Harry Potter: Wizards Unite (Mentioned only)