Based on the exploratory study of a 3D multiuser virtual environment (3D MUVE), known as Quest Atlantis (QA), in a series of Primary Four (10- to 11-year-olds) Science lessons at Orchard Primary School in Singapore, this paper examines the issues of learning engagement and describes the socio-cultural context of QA's implementation. The students and teacher were observed during the lessons, interviewed after, and the completed quests were analysed to determine the level of engagement achieved. A pre- and posttest on the Science concepts covered was also administered. A seven-level taxonomy of engagement was used to provide the study with a more holistic perspective of engagement, together with the attempt to concretise the element of engagement into observable traits. Although there was a significant improvement of the posttest over the pretest, the level of engagement of the students was low (between 3 and 4). The lack of engagement might be a result of the distractions in the 3D MUVE, the students' difficulty with language used in the QA, their lack of computer competency for QA tasks, andor their inability to complete the quests' section on reflections. The biggest challenges to the integration of QA into the Science curriculum were the interdependent issues of time (or lack of it) and 'buy-in' by the school and parents.