It started with a regular day last week at the playground near their Housing Board flat for the pregnant woman and her daughter.
But on Saturday night, the young girl came down with a fever.
Her family took her to the polyclinic and they were eventually referred to the hospital.
The diagnosis: Zika.
But the more troubling news came on Wednesday, when the mother, who is more than five months pregnant with her second child, found out she had been infected as well. She suffered "mild symptoms" and was taken to KK Women's and Children's Hospital.
She became Singapore's first pregnant woman to be infected with the Zika virus, the authorities announced that night.
"We were so anxious and couldn't sleep well," said her tearful mother-in-law, as she recounted the ordeal to The Straits Times at their home in the Aljunied Crescent and Sims Drive area yesterday.
All seems well now, after two days of checks at the hospital, and her expectant daughter-in-law will be returning home soon, she added with relief.
She declined to be named.
"We were worried and afraid, but we are feeling a bit better as my daughter-in-law is well now.
"She just has to go back later for check-ups regularly," said the woman in Mandarin.
Her daughter-in-law is still in hospital, and her health and her baby's development are being closely monitored. She will also be referred to a maternal-foetal medicine specialist for counselling.
Unborn babies in the first trimester and early part of the second trimester are most vulnerable to the Zika virus' effects.
This means that the baby of the woman - who is now in the later part of her second trimester - may still face some risks.
Dr Leong Hoe Nam, an infectious diseases specialist at Mount Elizabeth Novena Hospital, however, counselled perspective.
Unborn babies whose mothers are infected by the Zika virus may be born with microcephaly, a condition where a baby has an abnormally small head. The risk of this ranges between 1 per cent and 13 per cent.
But Dr Leong said the data is "horribly skewed" by Brazil, which reports a higher rate of microcephaly.
In French Polynesia, the risk stands at 1 per cent, and Dr Leong believes Singapore is likely to face a similar rate.
If there had been a change in the virus, the risk of microcephaly in Brazil would have extended to Colombia, but this is not the case, which means the risk depends on situational change, he added.
Dr Leong also said that in all live births, the risk of defects is around 1 per cent as well.
The pregnant woman is among a total of 151 Zika cases in Singapore as of yesterday noon. It is unlikely that she was infected because of her daughter or vice versa, as their symptoms emerged around the same time, said health experts at a briefing on Wednesday.
The mosquito-borne disease's symptoms are generally mild in adults.