This paper reports the development of a digital escape room for high school students using Genially, a web-based media platform. The escape room was used to aid understanding of basic concepts in chemistry and mostly enhance students' classes participation during the COVID-19 pandemic. The activity entitled "The thalidomide mystery" covered the concepts of chemical bonding, pH, acid and base, and laboratory glassware. The narrative of the game revolves around the drug named thalidomide; this drug was developed in the 1960s and its use caused several cases of phocomelia. WhatsApp chat groups were formed to stimulate an active engagement of the participants and maintain a collaborative and cooperative learning experience among them. Students were required to solve four chemistry puzzles to obtain the final password to reach the end of the game. The results obtained showed that the game was very useful for students mainly because it presented an innovative way of teaching chemistry, different from the traditional way in which the students are usually taught in their classrooms. The game helped the students to review the contents covered and was able to stimulate the active participation of both the students who like to study chemistry and those who do not.