Lisa Miller thought she’d be dancing alongside her three daughters at a Taylor Swift concert on August 8 . Instead, she found herself on the streets of Vienna, hugging a stranger in the street, united in a kinship formed by disappointment and a determination to fight hatred with harmonies. Miller and her family had their European adventure on the books long before their Swift detour was baked into the plans, she told CNN via email.

When she and her husband realized the superstar singer’s Eras Tour would be stopping in Austria at just the right time on their itinerary, they jumped at the chance to surprise their daughters, ages 8, 11 and 13. “My girls were ecstatic when we told them, and have been talking about it for months,” the Austin, Texas resident said. On August 7, the Millers became one of the thousands affected when Swift’s three nights of concerts in Vienna were canceled after police in Austria said they foiled plans for a terror attack at one of the shows.

Three teenagers have been detained in connection with the investigation and are suspected of plotting the suicide attack. Investigators found a stockpile of chemicals, explosive devices, detonators and €21,000 (about $22,944) in counterfeit cash at the home of the main suspect, a 19-year-old ISIS sympathizer who had been radicalized online, according to authorities. The young man – who was arrested Wednesday morning in the eastern town of Ternitz – planned to kill “a large number of people” in .