。、！
Darren, who is about to face the trial. If he fails — execution!
Literal
Trial [object-を] receive-become-past Darren. Fail-[if-ば], death-penalty!
Dramatic subtitle/synopsis style. The first sentence is verbless: a description with a relative clause 試練を受けることになった ('became (the situation of) to receive the trial') modifying ダレン (Darren). ~ことになる ('come to X, it has been decided that X') is a passive-sounding way to describe impersonal developments. The short exclamation 'If he fails — execution!' uses ~ば + noun, omitting the copula for dramatic punch.