<p>We study chiral algebra in the reduction of 3D <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\mathcal {N} = 2 \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="script">N</mi> <mo>=</mo> <mn>2</mn> </mrow> </math></EquationSource> </InlineEquation> supersymmetric gauge theories on an interval with the <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\({\mathcal {N}}=(0,2)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="script">N</mi> <mo>=</mo> <mo stretchy="false">(</mo> <mn>0</mn> <mo>,</mo> <mn>2</mn> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> Dirichlet boundary conditions on both ends. By invoking the 3D “twisted formalism” and the 2D <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\beta \gamma \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>β</mi> <mi>γ</mi> </mrow> </math></EquationSource> </InlineEquation>-description, we explicitly find the perturbative <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\overline{Q}_+\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover> <mi>Q</mi> <mo>¯</mo> </mover> <mo>+</mo> </msub> </math></EquationSource> </InlineEquation> cohomology of the reduced theory. It is shown that the vertex algebras of boundary operators are enhanced by the line operators. A full non-perturbative result is found in the abelian case, where the chiral algebra is given by the rank two Narain lattice VOA, and two more equivalent descriptions are provided. Conjectures and speculations on the non-perturbative answer in the non-abelian case are also given.</p>