。
I returned to my armchair and opened my book.
Literal
I [topic-は] armchair [to-に] return book [object-を] opened.
A short narrative sentence with 俺 ('I,' rough/masculine first-person), marking the narrator as casual-masculine register. アームチェアー (armchair) is a loanword — Japanese often uses a loanword for the specifically 'Western-style' armchair, as opposed to 椅子 (the general word for 'chair'). Two verbs chained with the written-connective form (戻って → 開いた), giving a clean 'returned and opened' sequence.