'This is the public version of the story. Kirika knows about it too.' 'So does that mean there's a hidden version?'
Literal
''Here-until [topic-は] surface-side [possessive-の] story is. Kirika-san [also-も] know-[state-ている] thing is [confirmation-ね]'' ''So-means, back-side also exists [question-んですか]?''
A dramatic reveal-teasing line. 表向き (おもてむき) and 裏向き (うらむき) are contrasting compounds: 'surface-facing (public)' and 'back-facing (hidden, private)'. These play on the Japanese metaphor of 表 (front/public) vs 裏 (back/hidden). ってことは ('which means, so this means') draws a consequential inference. 知っていること ('the thing of knowing') turns the knowing into a nominal.